So, the other day, I've played Amnesia: The Dark Descent.

It's scary. Quite scary, even. Yes, I would go as far as to describe it as genuinely terrifying. The athmosphere it has created in that first hour I played was amazing. There's no wonder its so easy to find reaction-videos of people screaming in fear for this game (though don't watch them so you don't spoiler it).
So if you like that kind of experience, by all means, go and buy it and support those developers! Not sure? Have a Review then!

I've also played Project Zero/Fatal Frame, which was also very scary (though it's far, far less so than Amnesia), and before that, Resident Evil 4 (which isn't very scary to be honest).

What other games of that kind does this community enjoy and recommend?

I especially loved their previous game penumbra and even more its first extension.
Less scarry, but also with a great atmosphere and awesome gameplay.

I can only recommend Dead Space 2. Maybe it´s not that scary, but the Athmosphere is awesome!!

If you like Amnesia, then I HIGHLY recommend Silent Hill 2. But don't go and try Dead Space, I've only played the first part and it really disappointed me. It's not scary at all, rather slightly startling at best. Kinda like Doom 3, only prettier and with slightly better atmosphere.
As far as I can tell, "Call of Cthulu: Dark Corners of the Earth" looks quite promising, but I never actually had the opportunity to play it. Somebody also told me that Condemned is quite scary. But then again, that person also likes Resident Evil....

BUT if you want to check out some other awesome and quite frightening indie horror game, go and give Cryostasis a try, you won't regret it. Provided you like quite slow pacing and movement. Personally, I really enjoyed it.

Ctulhu wasnt very good, unfortunately.
RE5 sucks donkey balls, but RE4 is hands down the best in the series.
Ofcourse 1,2,3 are great, but nowadays only fans can really digest that type of slow gameplay anymore (me :D).

And yes, Condemned (not the 2nd part) is really scary!

enjoy

I had seen the demos and reviews of Amnesia, so I knew it was great. But I just bought a copy yesterday, and it really is something else. It's a casual game, but it's got style... Unlike other casual games, like UNO for XBLA.

I'd agree with you that it's terrifying, too. This is the first time I've felt that way about a game. The whole experience is like watching Alien for the first time.

I always split horror games into 2 categories:
1) "Scary" as sudden things appear, scream, scare you (you jump)
2) The atmosphere gives you a constant uncomfortable and spooky feeling but you don't get just instantly scared (people jump infront of you saying BOO!).

I don't like the first ones. I don't like it to jump and get scared. It's kinda a lame way to scare people, its way too easy.
But creating an atmosphere where you feel terrified all the time even, or especially, if nothing happens at all, is just awesome.

So yeah i watched a lets play of Amnesia and it was really scary already, even though i didnt play it, but they did a really good job with that game.

Games like the new RE games or dead space 1/2 sucks. Dead Space 2 really pisses me off when i watch people playing it. Feels like 80% of your time you stump on dead body parts to get items, and its just gross and annoying And i never felt scared in any situation, except for those "instant appear and make BOO" scare moments, which sucks.

One of the scariest games i've played is Clock Tower 1... that scared the shit out of me when i was younger, especially when i once got so scared i pulled out the Playstation controller and couldn't run away, i freaked out and pulled the plug

i found the first system shock extremely scary as a teenager. especially when playing in the middle of the night in a dark room.

...but i don't like such games at all anymore. why should i make myself feel miserable? there are better things to do.

You feel my pain, then. Imagine spending an entire afternoon doing just that.

I loved Cthulhu! It's the best horror (and detective) game I've ever played!
I liked Silent Hill (best for me is 2 and 4, rest are suck). RE4 is just awesome!
But truly speaking, I've never played (or even watched horror movie) witch really scared me and made me shit my pants!