Didn't know that, with Indian I assume India since Indian is considered to be a racist term here in Canada for native americans...

well "Indian" may be incorrect, but I think it's a little far to consider it racist

Greek Empire 9
American Empire 11
British Empire 11
Roman Empire 12
Mongolian Empire 12
Chinese Empire 10
Persian Empire 10
Ghurid Empire 9
Japanese Empire 10
Ottoman Empire 11 (+1)
Akkadian Empire 9
Egyptian Empire 9
Islamic Empire 11
Byzantium Empire 10
Israeli Empire 7
Mughal Empire 10 (-1)
Comanche Indian Empire 10
The Ottoman Centuries is a really good book on how successful the Ottomans were. The Mughal Empire while briefly powerful it's corruption and mismanagement keeps it from being truely "great"

Greek Empire 9
American Empire 11
British Empire 11
Roman Empire 12
Mongolian Empire 12
Chinese Empire 10
Persian Empire 11 (+1)
Ghurid Empire 9
Japanese Empire 10
Ottoman Empire 11
Akkadian Empire 9
Egyptian Empire 9
Islamic Empire 11
Byzantium Empire 10
Israeli Empire 6 (-1)
Mughal Empire 10
Comanche Indian Empire 10
Everyone has pretty much agreed that the Israelis don't deserve to be on this list.
I gave the Persians +1 because nobody has given them love and with the largest population (as % of world population) of all time, they really belong on the list of greats.

People generally remember them for their fall (greeks) but they did a lot of good things before that...

Greek Empire 9
American Empire 11
British Empire 11
Roman Empire 13 (+1)
Mongolian Empire 12
Chinese Empire 10
Persian Empire 11
Ghurid Empire 9
Japanese Empire 9 (-1)
Ottoman Empire 11
Akkadian Empire 9
Egyptian Empire 9
Islamic Empire 11
Byzantium Empire 10
Israeli Empire 6
Mughal Empire 10
Comanche Indian Empire 10

ROME (+1): The Romans rewrote the record books on the magnitude, strength, and limits of empire, and they did it at a time when they were not the only game in town. I also don't think you can completely divorce the Byzantine or Eastern Roman Empire from the Roman Empire, as it was really an extension of Rome (one of four divisions that survived after the Western Roman Empire fell). Separately, they were both enduring empires, and together, they were the most enduring empire in history. In it's heyday, Rome's military, engineering, legal, economic, administrative, artistic, literary, religious, and social (diversity of population and incorporation of conquered peoples) achievements were among the greatest of any civilization. And later, Byzantium preserved much of Roman values and traditions while also reconquering and creating a later empire. We would know far less about ancient history and the story of civilization had it not been for the Byzantine.

JAPAN (-1): Hitting China over the head when they were down (which is what ranks them here at all) and the length of time the Japanese were even able to hold onto their spoils do not an empire make. I also don't think the Japanese of this period contributed as much to the advancement of civilization as many of the other empires on this list.

A little late to the party, but you guys should have considered the Aztecs as well... Their overall land control/population control may have been lower than others on your list, but they lived in a world with far fewer people and far smaller land to control. They effectively conquered massive amounts of Mexico, either by enslaving other smaller tribes or by allying with them and annexing them into the empire. It was the most wealthy of all the pre-European Western world(followed by Inca). They also had the largest standing army between the three major Latin American Empires(the Mayans were in quick decline at this time and the Inca's were not as militant as the Aztecs). Now I am not saying the Aztecs would hold up in competition as number one against lands like Rome, Britain, and others, but they should still be considered as one of the greatest empires ever, especially in the Western world.

That said:
Greek Empire 9
American Empire 11
British Empire 12(+1)
Roman Empire 13
Mongolian Empire 12
Chinese Empire 10
Persian Empire 11
Ghurid Empire 9
Japanese Empire 9
Ottoman Empire 11
Akkadian Empire 9
Egyptian Empire 9
Islamic Empire 11
Byzantium Empire 10
Israeli Empire 5(-1)
Mughal Empire 10
Comanche Indian Empire 10

The British had an extremely strong navy, a vast overseas empire, and large amounts of trade in hundreds of different ports around the world.
The Israeli empire just needs to be removed. how are they on there in the first place?

When we talk of the Chinese Empire are we referring to the modern day empire, the Ming, or Qin? Or just the Chinese Empire in broad terms?

Greek Empire 9
American Empire 11
British Empire 12(+1)
Roman Empire 13
Mongolian Empire 12
Chinese Empire 11 (+1)
Persian Empire 11
Ghurid Empire 9
Japanese Empire 9
Ottoman Empire 11
Akkadian Empire 9
Egyptian Empire 9
Islamic Empire 11
Byzantium Empire 10
Israeli Empire 5
Mughal Empire 10
Comanche Indian Empire 9 (-1)
I'll just give China one point because of all the strong Chinese Empires that have existed
I don't think the Comanche Native American Empire is that great really.

Derp, ignore the extra +1 for the British

Greek Empire 9
American Empire 11
British Empire 12
Roman Empire 13
Mongolian Empire 12
Chinese Empire 11
Persian Empire 11
Ghurid Empire 8 (-1)
Japanese Empire 9
Ottoman Empire 11
Akkadian Empire 9
Egyptian Empire 9
Islamic Empire 12 (+1)
Byzantium Empire 10
Israeli Empire 5
Mughal Empire 10
Comanche Indian Empire 9

Islamic: Along with the reasons I listed before, I feel like their effect on the world at the time, and their lasting effect secure their role as one of the greatest empires in history. At their peak, they were unmatched culturally, architecturally, economically, scientifically, etc. Plus, I've always been drawn to them, so they get my vote.

Ghurid: Maybe this is just a result of poor education in history; although I strongly doubt that, but I have never heard of the Ghurid when discussing the great empires of history. So for lack of relevance, they get my down vote.

Also, when we're talking about the Chinese Empire, which dynasty? Or just their entire history? Same goes for the Greek. Are we talking about Alexander's empire, or Greece following the Persian Wars under the rule of Athens?

Hey could I add a vote for the Inca Empire? It was not that large in terms of area but it stretched, at its heights through around 30 degrees of longitude and from the peaks of the Andes (and beyond in places) to the West coast of South America. This means it was dealing with a huge variety of climates when compared with other empires whose spread was mostly East to West). They did this without the wheel and without metals other than gold.

Greek empire 9
American empire 11
British empire 12
Roman Empire 14 (+1)
Mongolian empire 12
Chinese empire 11
Persian empire 11
Ghurid empire 8
Japanese empire 8 (-1)
Ottoman Empire 11
Akkadian empire 9
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Israeli empire 5
Mughal empire 10
Comanche Indian empire 9

First as the person who brought up the Israelis initially, you can take them off the list. I never meant to say they were the greatest empire just making sure they were recognized for their achievements and contributions to society, now if we were talking greatest individual culture or something like that I would put them near the top.
As for the Romans I give them a plus one because almost every empire after them claimed their legacy Britain, Germany, and Russia did. The American founders considered themselves heirs to the roman republican tradition. Even the ottoman sultan took on th title "emperor of the Romans" for a time.
Japan on the other hand was too isolated for a long time and when they did meet the west the entire shogunate collapsed. At their height most of what they had was empty ocean and a bunch of islands that were only of value as airbases and naval bases. Not to mention they thought it was a good idea to simultaneously challenge the two greatest naval powers to ever exist.

Greek empire 9
American empire 11
British empire 13 (+1)
Roman Empire 14
Mongolian empire 12
Chinese empire 11
Persian empire 11
Ghurid empire 7 (-1)
Japanese empire 8
Ottoman Empire 11
Akkadian empire 9
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9

Ok, it's clear the Israeli Empire is going away, so I've removed them.

BRITAIN (+1): The farthest reaching and largest empire area-wise in modern times, father of the industrial revolution (though this could be a bad thing if we don't address the fallout from this), and great achievements too numerous to list.

Ghurid Empire (-1): The ancient Persian Empire is far more worthy of consideration. Like the Israeli Empire, I don't think the Ghurid Empire belongs on this list.

If we were to add empires, Spain and Germany would also be in the running to be added with Inca and the Aztecs

Greek empire 9
American empire 11
British empire 14 (+1)
Roman Empire 14
Mongolian empire 12
Chinese empire 11
Persian empire 11
Ghurid empire 7
Japanese empire 8
Ottoman Empire 11
Akkadian empire 8 (-1)
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9
I'm giving one point because Scotland was the homeland of my biological father's ancestors and they were a great empire, blah, blah
While a strong miltary power the Akkadian didn't have much of a legacy in language, culture, religion, arts, etc so I don't think they can be considered that great of an empire

Without detracting too much from the most erudite discussions and arguments above, may I be permitted to nominate the Holborn Empire?

Chanteuses and comedians, trick cyclists and performing dog acts - much more civilised than some of the "official" entries in this tourney!

Holborn Empire is a corporate empire not a state empire so it doesn't really count...

Greek empire 9
American empire 11
British empire 15 (+1)
Roman Empire 14
Mongolian empire 12
Chinese empire 11
Persian empire 11
Ghurid empire 6 (-1)
Japanese empire 8
Ottoman Empire 11
Akkadian empire 8
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9

We are all speaking English today for a reason, because of British and American imperialism in the 19th century. Back then Britain was the world power.

As I said before, Ghurid empire is the only one on this list that I no nothing about, I just checked the wiki page on them, and its nothing impressive. They ruled over Persia for 70 years. The mongols did it for longer and did a lot more.

Greek empire 9
American empire 11
British empire 15
Roman Empire 14
Mongolian empire 12
Chinese empire 12 (+1)
Persian empire 11
Ghurid empire 6 (-1)
Japanese empire 8
Ottoman Empire 11
Akkadian empire 8
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9

The fact that China still exists as a nation and has expanded its borders constantly since thousands of years ago is a testament to the strength of the Chinese Empire.

Forgot to vote for -1. The one above doesn't count.

Greek empire 9
American empire 11
British empire 15
Roman Empire 14
Mongolian empire 12
Chinese empire 12 (+1)
Persian empire 11
Ghurid empire 6
Japanese empire 7 (-1)
Ottoman Empire 11
Akkadian empire 8
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9

It was all a dream. The Japanese thought they could rule Asia. But the US said no.

This is quite silly - it is very obvious that the best empire in history is the Atlantean empire, followed quite closely by it's arch-rival the Lumerian empire.

Greek empire 9
American empire 11
British empire 15
Roman Empire 15 (+1) Ave Caesar!
Mongolian empire 12
Chinese empire 12
Persian empire 11
Ghurid empire 5 (-1) the what ?
Japanese empire 7
Ottoman Empire 11
Akkadian empire 8
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9

Just a question, but can we vote more than once as long as we vote for different people?

I will bite the bullet

Greek empire 10 (+1) Equal weapons guys - unlike the British(! ) - knock out the biggest empire of that time)
American empire 11
British empire 15
Roman Empire 15
Mongolian empire 12
Chinese empire 12
Persian empire 11
Ghurid empire 4 (-1) the what ?
Japanese empire 7
Ottoman Empire 11
Akkadian empire 8
Egyptian empire 9
Islamic empire 12
Byzantine empire 10
Mughal empire 10
Comanche Indian empire 9

I think we can knock out the Ghurids
Greek Empire 10
American Empire 11
British Empire 15
Roman Empire 15
Mongolian Empire 12
Chinese Empire 12
Persian Empire 11
Japanese Empire 7
Ottoman Empire 11
Akkadian Empire 8
Egyptian Empire 9
Islamic Empire 12
Byzantine Empire 10
Mughal Empire 10
Comanche Indian Empire 9

Greek Empire 10
American Empire 11
British Empire 15
Roman Empire 16 (+1) Not much to say that hasn't already been said - for one, the British Empire would never have existed if they hadn't invaded England. Since I gave Britain a +1, it makes sense to give Rome one also.
Mongolian Empire 11 (-1) I think someone took one off the Brits for bad treatment of their foreign citizens, so I think the Mongols need to get a -1 for that too. They massacred a massive amount of civilians in their empire.
Chinese Empire 12
Persian Empire 11
Japanese Empire 7
Ottoman Empire 11
Akkadian Empire 8
Egyptian Empire 9
Islamic Empire 12
Byzantine Empire 10
Mughal Empire 10
Comanche Indian Empire 9

Greek Empire 10
American Empire 11
British Empire 16 (+1) The first empire on the list with truly global outreach. No matter where you were, if you weren't living an autarchic society, the relations with Britain affected you in some way.
Roman Empire 16
Mongolian Empire 10 (-1) Their exploits lied exclusively in supreme military power - training, equipment, tactics, leadership &c. The relatively liberal, syncretistic rule stemmed from their acceptance of their inability to effectively rule themselves, which led to decentralization and liberalization in areas they knew nothing about (the non-military stuff). The traditional powerhouses in Central Asia or Iran never reached their previous glory after the Mongol swept through them.
Chinese Empire 12
Persian Empire 11
Japanese Empire 7
Ottoman Empire 11
Akkadian Empire 8
Egyptian Empire 9
Islamic Empire 12
Byzantine Empire 10
Mughal Empire 10
Comanche Indian Empire 9

I’ll stay coherent with my earlier posts:

Greek Empire 10
American Empire 11
British Empire 16
Roman Empire 17 (+1)
Mongolian Empire 9 (-1)
Chinese Empire 12
Persian Empire 11
Japanese Empire 7
Ottoman Empire 11
Akkadian Empire 8
Egyptian Empire 9
Islamic Empire 12
Byzantine Empire 10
Mughal Empire 10
Comanche Indian Empire 9

+1 Roman Empire
Pax Romana, a primate of peace (in terms of years and people involved) in ancient History, maybe in the whole History.

-1 Mongolian Empire
I didn’t remember the size regarding slaughters carried on by the mongols, so I checked on wiki:
Take a look at the “Perceptions” paragraph
http://en.wikipedia.org/wiki/Genghis_Khan#Mongol_Empire
That’s the price for the so-called Pax Mongolica.
Those numbers about killings and destructions make Stalin and Hitler look like beginners… despite those 2 guys having much more tools and technology at their disposal.

Once I realized the last option was there, I knew I had to give it at least one more shot:

Greek Empire 10
American Empire 11
British Empire 16
Roman Empire 17
Mongolian Empire 9
Chinese Empire 13 (+1) The amount of comebacks Chinese empire in its various forms made is completely unprecedented. Its everlasting influence is well worth a +1.
Persian Empire 11
Japanese Empire 7
Ottoman Empire 11
Akkadian Empire 8
Egyptian Empire 9
Islamic Empire 12
Byzantine Empire 10
Mughal Empire 10
Comanche Indian Empire 8 (-1) An empire should fulfill certain criteria of statehood. Of all the native Northern Americans powers, only Mississippian culture ticks sufficient amount of boxes in that regard. And even that was in decline once Europeans made contact with it so measuring its true strength is problematic. I don't take the claim that Comancheria was a genuine empire seriously.