I remember watching the original A Nightmare On Elm Street when I was younger, and the scene where the guy sees the clear plastic body bag moving through the hallways of the school(complete with blood trail) totally freaked me out! The first one was mainly a horror movie with a little bit of humour thrown in, but all the sequels became campy movies rather than horror movies. I enjoyed them, but they didn't really scare me.
Another movie the scared the living heck out of me(even though I have never seen the first half of the movie for various reasons) when I was a kid was Children Of The Corn.
"He wants you too, Malakei, he wants you too."