Singleplayer FPS.. hmm. Here's a few I enjoyed and why.
Not human revolution, the first one. Pretty much one of the best FPS stories ever created, well worth a playthrough.
EYE: Divine Cybermancy
Very similar to Deus Ex but this one runs on the Source (HL2) Engine, very smooth gameplay spikes of complexity and understanding, because the translation is poor, the story lacks a bit, but at the price it is on steam right now, you can't say no.
There is nothing that isn't amazing about this game, graphically intense, amazing soundtrack, beautiful surroundings, excellent smooth freerunning gameplay. Although short has one of the best campaigns.
Throw Fallout and Deus Ex in a mixing bowl and you get STALKER, fantastic game similar to both the aforementioned games. Less linear than Deus Ex, but not as free roaming as Fallout.
Again well worth a play just for the classic story and intense fast-paced gameplay. The unreal pack is cheap on steam right now I think.
Medal of Honor
Basis predecessor to BF3, similar in many ways. The game was created for its multiplayer but didn't really take off.
ArmA 2 Operation Arrowhead
This game is borderline war simulation, but by no means should be treated like one. Behind the fact that this game is needlessly complex is a great storyline and offers a good learning experience.
Hope that helps a bit. If all else fails, some of these also have good multiplayer to fall back on. I'll just mention that other than Mirrors Edge, I don't really mention graphics too much. If graphics are something you care about more than story then some of these might not be for you, as they date back to late 90's in graphic quality.