"Welcome to Woop-Woop" was a very disturbing movie. Sone dude encounters an Australian redneck town that would put most US redneks to shame. Nothing SCARY per se, just REALLY F-ed up
Volcano: a silly movie, but there's one scene where a dude is trying to save someone and jumps into the lava so he can toss the person he saved to safety. He slowly melts as we watch him get shorter and disolve.
Signs: The video taped alien still gives me chills.
The preview for Gothika with the little ghost girl walking, but all broken (like missing frames of animation, or foottage filmed in reverse played backwards) is the first time I was ever scared watching a movie trailer
Galadriel in the first Lord of the Rings movie, she starts glowing and talking all scary. I don't know why, but that scene taps into some bizarre fear in me. I was cringing like a 3 year old watching Freddy Kruegger and I was 20 years old >_> (I still can't place exactly what it is that scares me about it, and I still get the willies, but not as bad as the first time)
when I was a kid the scene in the Neverending Story when Fantasia is destroyed frightened me. Now the " big...strong...hands" scene fils me with sorrow.