Salem's Lot damn near killed me. I was 5 years old (my mom raised me on a steady diet of horror movies, it was awesome) and, at the point where Danny is hovering outside of Mark's window scratching on it, my uncle went outside and started scratching on the window behind me. I don't think I came out from under my bed for 3 days. To this day I have a hard time watching it.
The Others and The Sixth Sense also got me. I'm freaked out by ghosts very, very easily for some reason. The Others got me when she went into that room with the sheets covering everything and you heard the ghostly moans from somewhere in there. The Sixth Sense got me when the suicidal woman chased the kid out of the kitchen, and also when he saw the ghost of the kid with a bullet wound in his head. Oh, and the puking girl in his tent.