I'm a big Planescape fan, and I really love PS:T, but... I still think I enjoyed Baldur's Gate 2 more. Both games have excellent soundtracks.
Icewind Dale had a great beginning, but deflated soon afterwards. I played through Heart of Winter and didn't find it particularly satisfying (not a dungeon crawling fan so meh).
Icewind Dale 2 was probably the best infinity game for multiplayer. The 3rd edition rules were well implemented and character customisation was, dare I say it, fun. Singleplayer was pretty dull though. Had that fan mod feel to it.
The original Baldur's Gate was a solid game imho, but severely limited replayibility. The entire game just became a small prologue when the 2nd one came out (I felt the same way about Fallout and Fallout 2).
Throne of Bhaal was a suprisingly good and fitting ending considering the circumstances of its development.