Civ II is amazing, sure, but III was very very good (if flawed in places), and IV is the best entry in the series and, excepting SMAC, the entire genre.

Also if you want a Civ game that lasts longer play the Caveman 2 Cosmos mod for IV. You can start in 40,000 BC and go into the far future. The longest game length is like 14,000 turns.