Spooky/Scary/Creepy Ambient Music

Hello Comrades! I cannot begin to explain it, but I am one helluva fan for horror movie style ambient music. When I say horror movie style ambient music, I allude to things like the slow, quiet, mysterious background music that you hear when you explore the darkest, deepest, nightmare-ish hallways of some long abandoned facility in a game like Silent Hill or S.T.A.L.K.E.R. It’s great to have going on the ipod, whathaveyou, when you’re playing on some Zombie Mod somewhere or some other scary scenario.

Unfortunately my collection is extremely limited at the moment, and I was wondering if there was anyone who could point me to a good source for more. It’s pretty much just limited too the S.T.A.L.K.E.R. Shadow of Chernobyl soundtrack and some small excerpts from Silent Hill

Any and all help is appreciated
Tschuss