Well, it's kinda goofy and seemingly for kids, but Kingdom Hearts is a must I'd say. MGS 2, RE 4. And okami was different. Gran Turismo 4 was really fun.
I've been on another Dynasty Warriors 5 binge lately(usually happens every 5 or 6 months), I'd suggest that, just a good fun game to just kill crowds and crowds of solders over and over again.
Shadow of the Colossus
Ratchet and Clank
Ratchet and Clank: Going Commando
Ratchet and Clank: Up Your Arsenal!
Ratchet: Deadlocked
Devil My Cry 3
God of War 1 & 2
Killzone
Time Splitters
Time Splitters 2
Star Ocean: Til the End of Time
Red Faction
Zone of the Enders
Gradius V
Kingdom Hearts
Kingdom Hearts 2
Jak and Daxter
Metal Gear Solid 2
Metal Gear Solid 3
Midnight Club: DUB EDITION REMIX
Justice League Hero's
These are all part of my library, and I recommend them.