Though it'll ultimately depend on your tastes, here's my collection for you to cast judgement upon. I don't have a lot of the more commonly agreed upon 'great games' for PS3 though, mostly because I'm not a fan of FPS.

Little Big Planet
Dynasty Warriors 6
Bayonetta
Final Fantasy XIII
Tekken 6
Soul Calibur 4

I could probably be classed as a Tekken and SC veteran, so these games were a no-brainer for me to buy. But might not be up your alley. Then again, they make for good games if you've got friends over.

I don't want to get into another heated debate over whether Bayonetta should be played on PS3 or not, but bottom line is that it's a great game and it's very playable on the console.

Little Big Planet is awesome fun. You can't go past it, I reckon. It'll be cheap these days as well.

And Dynasty Warriors I picked up super-cheap. It gets boring real quick, if you ask me. But if you'd heard about the Dynasty Warriors series before this, then you'd already know that. xD