Rome cause of Half Priced Wonders. Yesterday I beat Deity, with a Cultural Victory (I know, it's different), I had 3 cities and the top 2 greatest cities in the world were Rome, and the city I built with the 100 Gold milestone Settler, Antium. The third city I converted from the Greeks. Rome had about 230 culture, with a Temple, Cathedral, Courthouse with Magna Carta, Shakespeare's Theatre, a large population thanks to Granaries, Aquaducts, and Great Persons. (All thanks to 60 production, I was building stuff in less than 10 turns).
I also find that Rome is the best for Cultural Victory. I built the UN the turn after the Greeks launched their Spaceship. I could've done it much earlier but I want to get a taste of the ICBM, which I launched once at the Mongols who were the largest but failed to capture one of my cities. I restarted and launched at the Greeks next, because they had the nerve to declare war at me at the end of the game, the first time we ever had a war.