3D Dot Game Heroes (top-down Zelda like game)
Alice: Madness Returns
Arkham Asylum
Bioshock 1 & 2
Castlevania: Lords of Shadow (very very much like God of War)
Demon's Souls/Dark Souls (haven't played Dark Souls yet but I'm assuming it'll be as good)
Dragon Age: Origins
Dragon's Dogma
Enslaved
Heavy Rain
inFamous 1 & 2
Kingdoms of Amalur: Reckoning
Nier
Rage (for the price, it's a lot of fun, but just... completely ignore the story)
Rainbow Moon (simple tactical RPG similar to FF:Tactics, but very easy to get into. PSN download title, $15, brilliant if you like the genre)
Ratchet & Clank (pick any title, they're all good, although All 4 One is the weakest of the lot in my opinion)
Rayman Origins (platformer, a nice mix between Mario and Sonic)
Spiderman: Shattered Dimensions
Uncharteds
Valkyria Chronicles