Lanefan
Victoria Rules
Which is, as fate would have it, about exactly what I've done with my current campaign: a rough cross between Classical Greece and Xena. The "Greek" empire is in serious decline - reduced to a few squabbling city-states, in fact - and the wolves ("Romans", barbarians, Elves, pirates) are circling.I voted for the Greek world because of the fragmented nature of the Greek world. That said, I think D&D is a bit OTT for a Classical peroid campaign though thinking about, it would fit ok with a Xena/Herclues the Legendary Journeys type treatment.
Greece is chaotic. Rome is lawful. Pick yer favourite and go.

Lanefan