Well since everyone that didn't say GoldenEye is WRONG you should pick up GoldenEye for certain! This is a list of what  FPS games to go with this gen.

GoldenEye = CoD4 = The Orange Box (okay most of the content is last gen and it's best played on PC no biggie though) > Left 4 Dead 1 & 2 > Battlefield Bad Company 2 > Halo 3 & Reach > Black Ops (if it was just multiplayer we were talking about it'd be on par with Bad Company 2) > Crysis 2 > Battlefield 1943 > World at War = Modern Warfare 2 

This would be my reccomended cut off line, then starts the if you really just played all those and must have more FPS in your life list.

The Conduit > Bulletstorm >  Halo ODST > Killzone 2 & 3 (which is sadly better than) > Resistance 1 & 2 (such a great developer making such a meh FPS game) 

Then you reach the unacceptable range for me

Homefront and the slew of other  FPS titles that hit this generation, anything made on a small budget you're going to want to stay away from basically.

Note I'm not counting things like Fallout 3/NV cause those would be highly reccomended but they're WRPGs with FPS elements.

Resistance:Fall of man has a pretty good engaging story & gameplay to it

Quake 4

PS: get the PC version

Metro 2033 is highly under-rated but worth checking out.

`Man, me and you are on totally opposite ends of the FPS spectrum bro. I mean, everything is just so wrong with this in my opinion 0_0. EIther way ill take every game you mentioned and list them out in my best to worst order. Just so you could see how different it is. Plus it will help the OP more. Haven't played the orange box or 1943 though. 

Halo Reach > Killzone 3 > Battlefield: BC 2 > Killzone 2 > Cod4 > Resistance 2 > Modern Warefare 2 >  Resistance 1 > GoldenEye >Left4dead >   Black Ops > Crisis 2(could be way better with pacthes) > World At War > Bulletstorm (no competitive is a nono.) >  Left4dead2 (it was litteraly almost a copy and paste, and i hate copy and paste). > The Conduit 

^^^are you guys forgetting that the OP wasnted SP only?? So Conduit and COD except maybe number 4 shouldnt even be on anyone's list. Halo is alright. But Bioshock's SP craps on just about any FPS SP ive played this gen. Hell even part 2 is better than most, dont let anyone tell you different. Left4Dead doesnt even have a story.

Is your computer even halfway functional? Could it run a game from, say, seven or eight years ago?

Killzone 2, Killzone 3, Bioshock

Only FPS that i play, i finished them more then twice.

Great singleplayer experience.

Well It depends what system you are talking about?

PS3: Killzone 3 (I would reccomend this the most)

Xbox 360: Halo Reach

PC: Crysis 2

I would say Killzone 3 or Reach. There really aren't any good new games for PC any more FPS are much better on PS3 and Xbox 360 these days.

Wow!  Thanks for the replies.  Well, I got a good deal for Metro 2033, so I decided to go with that.
So far, I am very impressed by the atmosphere. 

I guess The Orange Box and Bioshock also sound pretty good.

Unfortunatly, I only have an xbox 360, so I won't be able to try Killzone 3, and from what I have seen, it looks really, really good.

How about Battlefield: Bad Company?  I just saw it pretty cheap at Gamestop.  Just wondering.

Thanks!