Oh man, Poltergeist scared me to bits when I was younger. I had a tree outside that would scratch the window in high wind or storms and th whole tree-eating-Robbie part gave me nightmares. I was afraid to sleep in my room during storms for months,
Oh and when I was a kid the TV really did go to all static after the US Anthem came on. SO if my mom fell asleep on the couch I did wake up in the middle of the night to that spooky static. If you listened longenough you could convince yourself there were vioces, at least to a kid's imagination.
One of the scariest was Stephen King's "IT". "We all float down here." Yikes! I was afraid to go into the bathroom alone foever.
As I got older there was Nighmare on Elm Street, our favorite scary movie for sleepovers.
And actually Diary of Emily Rose frightened me. I was practically climbing up my husband's arm while watching. ^^
Oh, and I can't forget the best horror movie of all time IMO - The Shining!