Depending on your age and what you're exposed to, there has to be a movie that absolutely scares the piss out of you. Mine would have to be Pet Cemetery. I saw it when I was young and it's stuck with me ever since.
House of 1000 Corpses is the prequel to this film and i love them they're full with blood and gore and defiinetly not for weak nerves but they're great
blair witch project was a great film an nosferatu and old german vampire film both are really scary on their own style
(by the way i've got the feeling we both do some fightposting style thing.......forget it i'm sitting here and post still when you are already asleep^^)