Ba-Ba-Ba-Baldur's Gate 2. (the first one was great too, but no awesome characters, and too many empty wilderness areas)
BG2 hosts some amazing characters (not Minsc), but the two that stand out the most are (not Minsc) Jaheria and (not Minsc) Viconia. (not Minsc)
Seriously, complex as all hell, each with a heart-wrenching romance plot which I find unbelievably involving even after dozen of playthroughs. It saddens me that Minsc is the one getting all the love after all these years. Fuck Minsc. And while we're at it, fuck HK-47 too.
Not to mention that the game has the riches world I've ever experienced in a video game. No RPG compares to it, not even Torment. I could go on and on about this masterpiece...
It is, quite literally, the perfect RPG.
Other games I like:
Half-Life 2
Thief: The Dark Project
Deus Ex
System Shock 1&2
The Longest Journey
Planescape: Torment
Spyro: Year of the Dragon
Duke Nukem 3D
KotOR I&II