Horror games lol. I never cared much for the genre because it seems like most of them get you scared by having things jump out at you. That's actually fine by me, but not when it's contrived. Hell Shadowgrounds made me leap out of my seat multiple times and I loved it, but it sure wasn't scary. I do like Dead Space actually, but for the awesome atmosphere.

A game doesn't have to be a horror game to be scary, in fact the scariest games I ever played were not horrors at all. What games need to do is create good characters, put them in peril.

Scariest moment in any game I ever played was the encounter with Sniper Wolf in the original Metal Gear Solid. I was like, "Holy shit is she dead?"
Followed by that was the notorious "Breakup" scene in The Darkness. I swear I nearly broke my thumbsticks trying to move. I honestly can't think of scene that made me more emotional. I couldn't believe it had happened, it was really that shocking. Amazingly the game manages to carry the momentum all the way to the end.