if its playstation, its always final fantasy and metal gear.

The PS3 games I'm most excited about at GTA IV, SSFIITHDR, WipEout HD, and LBP.

But to answer your question-
currently- GTA IV, MGS4, LBG, R2
future- FF 13, GT5, Uncharted 2

GoW + GT + MGS + KZ + Uncharted + LBP + Resistance & Then there are some stuff like Motorstorm, Rachet and clank but seriously though GT and GoW alone rapes big :O. MGS Was something i just discoverd and fell in love with so that pwns big mamas. But yeah GT is probably the biggest :P. I like Jak and dexter too... XD

Well since you named two games I am going to say MGS4 and LBP.

If Gears and Halo 3 seriousley still define the 360 for people that is sad.

MGS4 and LBP dominate the time I spend playing my PS3 and as a result define the experience for me. The only other PS3 game that I have spent any signifigant amount of time on was Uncharted and while it is a great game, it isn't up to the level of quality as the aforementioned titles.

I'm definitely not alone in still thinking of Devil May Cry and Grand Theft Auto as PlayStation brands. There were obviously a lot of people who picked up the PlayStation 3 with the express intent of purchasing those titles before their multi-platform statuses were revealed. Despite the large install base advantage the 360 has over the PS3, GTA IV on the PS3 has done quite well:
360 - 6.56 million
PS3 - 5.18 million

Sure, the 360 still has a substantial advantage in sales for GTA IV but it doesn't match up, proportionately, to other multi-platform titles.

Devil May Cry 4 on the PS3 has actually outsold the 360 version. I wasn't sure that these figures would stand the test of time but they certainly seem to have:
360 - 1.18 million
PS3 - 1.29 million

These aren't the figures you'd expect from a system that has an install base advantage of ~7.5 million systems and the only explanation I can come up with for it involves some sort of brand loyalty - though in the case of DMC4 at least, it just comes down to the Japanese numbers.

To contrast with the GTA IV numbers, we have Call of Duty 4:
360 - 6.85 million
PS3 - 3.9 million

HEATHEN!

 I agree with this, since "define" is such a strong word.

But all the nice million-sellin exclusives of course also help to form the character of the PS3 - Motostorm (as launch title), Resistance, God ov War, perhaps Killzone, LPB & Uncharted. And Lair of course. Final Fantasy 13 somehwat because of the historically strong association with Playstation.

sony's 1st party = the killer games on ps3

You really need to get gears2 and play it on hardcore I mean this is my goty.