I used to watch a lot of horror movies as a kid, but few scared me. Here are the select few : P.
Texas Chainsaw Massacre-The ORIGINAL- Scared the shit out of me because the realism (no blood, gritty film) and I thought it was a completely true story.
IT- C'mon it was about a demon CLOWN.
Halloween- The music scared my nuts off.
Candyman- Everytime I took a shit I stared at the mirror in shear terror.