Planescape is a must obviously. Oddly I'm just replaying it on my laptop.
I'm also going to put Temple Of Elemental Evil out there, especially for the guy who wanted AD&D based RPG. It's not an ultra amazing game as such but the combat system is pure awesome providing you know AD&D rules. Otherwise it's complicated and hard to get into. The plot isn't much and it's basically one big dungeon crawl.
Icewind Dale 2 I really enjoyed as well but once again pretty much a dungeon crawl.
I'm also going to put Temple Of Elemental Evil out there, especially for the guy who wanted AD&D based RPG. It's not an ultra amazing game as such but the combat system is pure awesome providing you know AD&D rules. Otherwise it's complicated and hard to get into. The plot isn't much and it's basically one big dungeon crawl.
Icewind Dale 2 I really enjoyed as well but once again pretty much a dungeon crawl.