Yes

Get Killzone 2, you won't regret it.

Whats with the Killzone 2 hate? Most people don't like it because they suck without aim assist

Killzone 2 ftw!

Seriously ?

Borderlands
CoD MW2
Resistance
Resistance 2

and if you play lots of multiplayer sessions then also:
Bad Company
Killzone 2

If I gave Far Cry 2 a second chance, I'm pretty sure I would also like it more then Killzone 2.

Can't be bothered right now though.

Killzone 2
Resistance: Fall of Man
Resistance 2

Nothing else really matters after that. It looks like you got 3 of the only multiplat FPS games worth getting. Most of the other multiplat FPS games suck, Far Cry 2 is a perfect example of this. You got a PS3, you might as well get the exclusives for it. Save the multiplats for afterwards. Some of the few good ones are the Tom Clancy games

KILLZONE 2 - this game just rocks.
Really takes FPS to another level - you won't find graphics/polish like this anywhere else.

There are haters of this game out there, but don't listen to them- they're the minority and often have an agenda of protecting another console's reputation.

Yes

This is of course only the single player campaign. I tried the multiplayer to Killzone 2 and it really didn't do much for me.  

Oh yeah, because only fanboys can dislike Killzone 2