Off the top of my head, the games I go back to the most are:
Hydro Thunder
Dynamite Cop
Sonic Adventure
Marvel vs Capcom 2
Power Stone
Daytona USA
Soul Calibur
Ready 2 Rumble
Bust-a-Move 4
NFL 2K2
NHL 2K2
NBA Showtime
Sega Bass Fishing (if you have the Fishing controller)
Star Wars Racer
Star Wars Jedi Power Battles (this game is a janky mess, but I love it)
Lots of others. Sega and Capcom in particular were at the top of their game.
Mars Matrix
Draconus: Cult of the Wyrm
Metropolis Street Racer
Tokyo Extreme Racer (1 and 2)
+Add any Midway Arcade title here (Including Gauntlet Legends)
+Add any Sega Arcade title here
+Add any Capcom Arcade title here
Berserk
Grandia 2
Record of the Lodoss War
This is my list (I know, I cheated with the Arcade bits but... DAMN they looked good!)