Ace Combat 5- eh....
Armored Core Nexus-no
Disgaea- haven't played it, doesn't look interesting
Phantom Brave- never heard of it
Gran Turismo 4- good, not great..we'll see how long it holds my attention
GTA: San Andreas- excellent, but coming to Xbox and PC as well
Street Fighter Ann. Collection- SF sucks, always has
Virtua Figher 4: Evolution- haven't played it, but I doubt it beats Tekken our Soul Calibur
Rez- never heard of it
Katamari Damacy- haven't played it yet, Blockbuster doesn't have it for rent, looks interesting, though
Final Fantasy series (mostly)- FF went downhill after VII...X was crap, so I never bothered with the rest
Onimusha 3- mediocre
MGS 3- mediocre
Tekken 5- Ok, I give you Tekken, best fighting series ever...haven't play 5 yet, though
Xenosaga series- :down:
Amplitude/Frequency- haven't played it, but I usually hate puzzle games
Castlevania: LOI-no
Devil May Cry 3- haven't played it yet, but considering the first one sucked, I'm not really looking forward to it.
R-Type Final-
Ratchet and Clank- crap
Jak- crap
Those are the ones I can think of off the top of my head, but that's certainly not a small list, considering that I covered about half of the PS2-exclusive games I consider worthwhile