I played (a little, admittedly) Baulder's Gate 2: SA
a while ago when Shrike recommended it to me, but he also recommended PlaneScape: Torment
, which I enjoyed and played more than BA2:SA. I need to play both more, and feel like actually buying them instead of using the torrents I got a while ago.
I'll add Fallout 2 to that list as well, and it's available on Steam.