I've played Civ II more than any other version. Must've been hundreds of hours. I played the original a lot, too.
I played quite a bit of III, perhaps about the same as Civ IV. I'm ashamed to say I sat on Civ V for over a year without playing it because I wasn't enamored with the idea of the new combat mechanic, but now I really dig it. I'll probably surpass III and IV at some point.