RPG is no contest, Baldur's Gate 2: Shadow of Amn, my first D&D game but I loved the challenge and I mastered it.
My FPS pick is CSS, after about 2 years I stopped sucking and started owning, now if only my computer didn't suck I'd own harder.
Currently in a bind on my MMO fix, haven't played WoW in a while (want to), it is a good game though and Blizzard does run a tight ship... on my other hand is Mabinogi USA from Nexon. Good game, bad company (which comes with free order of bad decisions.)
Personal Best game EVAR? Legend of the Dragoon for the PS1. No idea why, just love the game