For me, Fatal Frame has overwhelming atmosphere and personally terrifying enimies, which you fight off with a camera of all things. The game just gets under your skin, much like how j-horror films work.
F.E.A.R. and its sequel gave me some jump moments, which usually don't happen. Its hard to remember to be scared, though, when you go around vomiting bullets at everything that moves(and at some stationary targets as well.)
Doom 3 showed me how fun it is to play around in the dark. For me, making interiors pitch black is a cheap and effective way of creating atmosphere. To shoot things. I suppose its scary moments come from having enemies spawn from everywhere, making you pretty frickin paranoid and pretty fricken claustrophobic. If you think doom 3 isnt scary at all, you obviously don't think very much.
Dead Space had me more fearful of running out of ammunition than anything else. I enjoyed the sci-fi aspect though.
Penumbra: Overture was quite silly and sometimes annoying. Most enemies could be thrown into ragdoll submission by throwing handy objects at them, and then beat to death with your hammer/pickaxe/broomstick. The ending was predictable, not a whole lot of creativity into that.
The chemisty puzzle early in the game was completely uneducated, though.
Its spiritual successor, Amnesia the dark descent, had a stronger and more driving setting and storyline, but I'm not a fan of sitting in dark corners waiting for the "bad things" to pass, creatures who look like they should and are wearing paper bags over their heads, except the paper bags are made of flesh. I dunno, you'd think that some dude who could smash through slightly weakened stoned walls and wooden pillars with his bare hands could find a weapon to be a match for something with malformed and supposedly dangerous hands. I suppose if the developers implemented combat at all, it'd be as flawed as in Penumbra(so instead of fixing it, they removed it entirely.)
Resident Evil was too tedious for me to really get into. Some quality scares though when you go into a first person viewpoint to open doors, and occasionally get a savory suprise. I consider REmake to be one of the better parts of my gamecube collection.
The thing was a game I enjoyed playing. I don't know if I can really consider it terrifying though.
Condemned was like F.E.A.R. minus guns(guns aren't supposed to be primary weapons), plus detective work. The second installment wasn't as fresh as the first.
I havent played Silent Hill or Forbidden Siren as much as I'd like to, and while Silent Hill looks like a different flavor of Resident Evil, Forbidden Siren looks like a real good play.
My suggestions?
Ao Oni. I believe it is japanese for "blue demon." Its like final fantasy, except you don't fight and just run away from a giant blue thing that wants to eat your head. A Widget thing, and worth playing. Its freeware, but good luck trying to find up-to-date english patches.
Eversion. Its a freeware game, a platformer that plays like Mario. Try it.
System shock is a classic.
The Path. Indie game. postmodern retelling of the old tale of Red Riding hood. Manages to be quite unsettling despite the lack of a single enemy whatsoever. The closest thing to anything hostile is a stuffed dog in your grammy's house.
Clive Barker's Undying. FPS with few supernatural powers at your disposal, against a host of supernatural creatures. Some really unsettling moments. Play it, then complain.
Amnesia isn't a franchise... yet.
Whatever the thread is supposed to be about, people are really here to talk about scary games. It doesn't much matter if they've spawned many and progressively degenerative sequels, or are toted by bigshot videogame distributers as franchises.
None of games are actually scary I just happen to jump of my chair when something pops to my screen while I have no lights on. Its rather "OMGWTF" things that piss me off. Like in HL2 I was just hitting boxes with my crowbar and then headcrab jumped from the box even thought they dont even look more scary than overhyped crabs.
I consider a game "scary" where there are points in the game where I absolutely dread to traverse, for no discernable reason. Everyone has differing ideas as to what horror is though, I suppose.