Favorite: IX. Possibly the only RPG I've ever played that I'll gladly play through in full a second, third, forth time.

There weren't really any FFs that I all out hated... but there were several I don't really give a hoot about. V was the least interesting to me, but I never played through a sufficient amount of the game to deem it as my least favorite so I say VII. Not really a bad game, just a tad bit over-rated.