Doom II is one of the best games ever—it has a poetry to the play
most games never achieve.
Civilization 2 for obvious reasons.
Sims II for the nude patch and sex hacks that allowed one to
enact nearly all one's Freudian fantasies.
GTA San Andreas, GTA San Andreas, GTA San Andreas
(I used to wait for my roommate to go out, then take his CJ
on a fast food binge until he reached maximum fat—classic.)
I was going to say Fallout 3 for recent fave,
but how could I fail to include:
The Bilestoad!!!