BG1
Arcanum (curse you Troika! Great setting, crappy balance)
And a bunch of others I certainly forgot.
@Sand.
Haven't beaten F2? Tsk tsk. Do it, it's better than F1.
(I know this will now end in a dirty fight :'( )
I do like Fallout 1 better and beaten it several times, but I get to the Enclave oil rig, and well... I just haven't beaten it. My save game is long gone now, but at some point I really need to replay both Fallouts. Maybe when Fallout 3 is close to release I will play the originals so they will be fresh in my mind when Fallout 3 is released.