Call of Cthulu: Dark Corners of the Earth

I am not usually easily scared, but The cradle in Thief: deadly shadows did put the wind up me once or twice I must admit.
Other than that I suppose I can point to Aliens on the spectrum for giving me my first game orientated scare, I know I know....but in my defence it was the first time I had ever seen anything like it, and I may be wrong here but possibly one of the first times "survival horror" was attempted.

I'm not much for scares - sure, you may nearly piss yourself, fall out of your chair, or have a heart attack, but that's about it. The horror of realizing that something is very, very wrong; or the terror of anticipating that something will go very, very wrong - that's what I prefer in my scary games. Some games that I found were pretty good at creating such an atmosphere include:
- Call of Cthulhu: Dark Corners of the Earth. All I'll say is "shooting yourself in the head due to massive sanity loss".
- X-COM and Incubation: "impending doom" would be a nice way to describe them. Especially the former. The aliens are coming, and they're going to kill you. All of you.
- Alien vs Predator: see above, except now there's only one of you.
- Silent Hill and Sanitarium: are you one that's gone insane, or is that the rest of the world?

Not really a whole game, but a particular mission in Vampire: Bloodlines did give me the chills. One of the early missions in the game, you have to get an artifact from a haunted hotel. While creeping around the decrepit hotel, pictures fly off the walls and hit you, lights explode unexpectedly and you occasionally see a "lady in white" running around the corner, just out of your reach. All during this you are finding clues to the haunting that involve a family the lived in the hotel. The father went nuts, decapitated one of the kids and burned the wife alive in their room. It was very creepy stuff, but that atmosphere was not really maintained throughout the rest of the game.

You guys might think it's weird, but when I was little, I was scared to death of MYST. No one was there. I always thought something was gonna jump out at me.
Also, Magic Carpet 2 (God, remember when you went to a store to buy a Bullfrog game? The memories), Goldeneye, Wolfenstein 3D, TimeSplitters 2...
I'll just stop there.

My first exposure to Clock Tower on the PSX. Scared me to the point where it took over a year for me to touch it again.

Wow now that sounds cool. How old were you?

Forgot to mention that one, too. :)
Brilliant game, though.

I think I was... maybe fourteen or fifteen at the time. I'm twenty now.

CoC: DCotA was pretty impressive, it managed to create an atmosphere which gave me some chills (especially in the beginning, when you have no weapon). Afterwards it's kind of boring.
Doom 3 when it came out, now it does nothing on me.
Condemned: Criminal Origins was really scary too.
Can't remember any others...

Silent Hill 2. The other Silent Hills don't scare me, but 2 was weird and twisted enough.
Forbidden Siren, the enemies, mainly.
System Shock 2 is probably one of the creepiest I've played, though not outright frightening.

Games that I try not to play in the dark
1) Clive Baker's Undying
2) AVP 1 (Playing as marine was quite scary, especially when you are out of ammo)
3) System Shock 2
4) Diablo (In the Church underground level 2 with the "Butcher". Fresh meat..., anyone?)
No 4 was only scary on the 1st try though..:)

I thought that Condemned: Criminal Origins was very creepy. Playing that in the dark with volume up obscenely loud set an atmosphere for me that was similar but way worse than watching The Silence of the Lambs.
I feel kinda dirty for mentioning a console game here on a PC forum but like others have mentioned before me: Clock Tower for the PSX. After playing that game long enough I had been creeped out enough to appreciate slasher films on a different level.
Doom 3 was the most recent game to get my blood pumping while playing it (on hard) first time through but now...not so much.

Original X-COMs, when my big brother played them. Nothing quite as scary hasn't come out yet.

Very recently, the Penumbra Tech Demo scared the willies out of me, and them some.
If you haven't tried it yet, I'd recommend the free download, it's a pretty chilling first-person adventure which involves you sneaking into an almost-deserted underground bunker. The graphics are pretty good, and it has a fairly innovative control method for interacting with the environment.
Get it from here: http://frictionalgames.com/site/penumbradownload/