Silverflame
OBJECTION!
Depends, because believe it or not, civ fans are actually really general. Civ is addicting either because of several personal preferences in games: Turn-based, empire building, warfare, and history. So probably go with what others have said for the first three (and possibly fourth), but you might also like RTS. In which case, go to AoEII (not starcraft because it is so old, I think it costs as much as civII now ). I wouldnt know, youll have to decide on your own I guess.