@fasces I'd just like to say that regardless of our conflicting ideas on the Americans and Islamic empires, I have really, really enjoyed this thread. I have learned quite a bit and have had a really good times talking and reading about all this. But I have an idea. Why don't we keep going with this until there are only 5 left, then start a new thread (or continue on this one) with a new series of empires (Aztecs, Venetians, Spanish, Russian, etc) and wait until we have 5 left there, then add the two lists together and go until we have just one left? Maybe that's too ambitious, but I just really like this idea.
Anywho, here is my vote.
Greek (Athenian and Macedonian) Empires 9 (-1)
American Empire 11
British Empire 16
Roman Empire 17
Mongolian Empire 10
(generic) Chinese Empire 14
Achaemenid Persian Empire 12 (+1)
Japanese Empire 6
Ottoman Empire 11
Akkadian Empire 8
(pre-Ptolemy) Egyptian Empire 9
(generic) Islamic Empire 12
Byzantine Empire 10
Mughal Empire 10
Comanche Indian Empire 8
Greek: The little, history-loving kid inside me died a bit with this vote. While I would never deny the fact that Athenian art, culture, music, architecture and the such were magnificent, their government was also extremely corrupt. This was made worse by a claim of enlightenment and equality, which was a complete lie (the Melian Dialogue), and both the Athenian and Macedonian empires fell shortly after their peak.
Persian: Noted for their religious tolerance, a lack of slavery, and stunning culture, I have to give them my vote. I find they are often forgotten in the West, but rulers like Cyrus were truly Great. Plus, it was a combination of Greek and Persian culture that gave us the Hellenistic Period; which in turn was a founding element of the Renaissance, arguably the peak of European cultural output.