Aliasalpha: Hmm I came here hoping to find
Planescape Torment so that would be number 1 on my list. Others would include:
Both Syndicate games (ideally as a bundle)
Both Crusader games
Bioforge (Any game that contains the line "Return the fork or I shall command it to destroy you" shortly before you beat a guy up with his own severed arm has got to be a hit!)
Warhammer 40000 Chaos Gate
Caesar & Cohort 2 (I think that was the combo made to work together, always wanted to try that, strategic & city building in one game, battles in the other)
Settlers series
Stuff I already own but would re-purchase for vista compatibility:
Grim Fandango
Discworld Noir
Powermonger / Populous
TIE Fighter (Preferrably with added magic multiplayer that never existed anywhere but my dreams)
Oh, and I'm gonna trump you with X-Wing vs. TIE Fighter. Best. Game. EVER.