Seeing as how I just got a new one, I'm going to start looking for new games to play.
Already I have:
Powerstones 1 and 2
Crazy Taxi
Dynamite Cop (I think I have that one, somewhere...)
Sonic Adventure 2 (I'm pretty sure my friend has Sonic Adventure 1)
Soul Calibur (I think my friend has that one as well)
What else?