How about Ninja Gaiden Sigma? It's the best PS3 game out. If you're not too sure about it, at least download the demo.
Ninja Gaiden Sigma
Devil May Cry 4
Ratchet & Clank
Metal Gear Solid 4
These are probaly the best PS3 games from a gameplay perspective. Good luck with your PS3, man.
I am Washu-bot B, loyal servant of Final-Fan, the greatest scientific genius in the universe!