Resistance 1-3 (especially 2)
Infamous 1&2
God of War 3
MGS4

Disgaea 4!!

Uncharted 3
Killzone 3
God of war 3
Infamous 1+2
Littlebigplanet 1+2
Resistance 1-3
Metal gear solid 4
Journey (A must buy!)

lmao, PS3...

flOwer
Numblast

to name 2

Valkyria Chronicles/Demon's Souls(Dark Soul's too!)/Tales of Graces F

Should keep you busy.

*derp*
Forgot Valkyria Chronicles. It's a masterpiece.

the resistance series, 1 and 2 are pretty cheap right now
infamous
gran turismo

So I guess you'll be buying UC3 and KZ3 then :)

Demon's Souls
MGS4
Valkyria Chronicles (Best strategy game not on PC)
Disgaea 4 (But, lots of people tell me this is the best one..)
Yakuza 4 (better than 3)
God of War 3
Infamous series
Journey (PSN)
Folklore (hidden RPG gem)
God Hand

Shatter (PSN)

Closure (PSN)

PixelJunk Shooter (PSN) 

Super Stardust HD (PSN)

Siren Blood Curse (Wanna be scared shitless? No? Whatever, play this game anyway)

I recommend buying HD collections followed by its sequels, mainly God of War 1-3 and Metal Gear Solid 1-4. If you are interested in JRPG's then buy Valkyria Chronicles, Demon Souls or any other PS3 exclusive JRPG's that you are interested in. If there are multiplatform games that you haven't tried yet that you feel are suited towards, or perform better, on the PS3 then buy those too.

Heading into town, i think ill pick up god of war 3, and journey from psn for now. I played dark souls on 360, might get demon souls too. Resistance however doesn't appeal to me.