Horror Games

I would have to agree with SPC-Containment breech

 

I'm assuming you've played Silent Hill 2&3 and not just the newer western Silent Hill games? If the older Silent Hill games and Amnesia: The Dark Descent (not A Machine For Pigs) isn't doing it for you, I'm not entirely sure what will.

Personally I don't really consider F.E.A.R. to be a horror game. I know it's sort of meant to be, but it's really just more of a psychological/dark-themed shooter. Dead Space also doesn't really do it for me in the horror genre.

The only games I can think of to recommend are Penumbra: Overture and Black Plague (avoid the 3rd one (I don't recall the name), it's basically just a puzzle game), and Lone Survivor.

EDIT: Reading through this thread, I realized that I forgot Resident Evil 4. I know Joe mentioned it. It's definitely the best Resident Evil game. A great 3rd person, horror-themed shooter. Most RE games are based around survival horror but RE4 probably pulls it off the best. It has some genuinely tense moments and some pretty grim atmospheres.