Deliverance

Fire in the Sky. I was only 9, but that's the last movie that gave me nightmares.

The first two scary movies I saw were Psycho and The Birds. They were on TV and I was probably 10 years old. Scared the crap out of me. Overall, the Exorcist is the scariest. I saw it for the first time at the movie theater on a midnight movie screening. It had quite an impact.

Also, if anyone is into the low budget Blair Witch/Paranormal Activity style documentary horror movies, I highly recommend the web serial called Marble Hornets. Smallest budget, but I actually liked it the best of the three. You can find it on Youtube.

I saw Amittyville Horror when I was about 8 or 9. That one caused some serious nightmares for me for some reason.

I started watching this (the slender man) a while back -- I enjoy it but after reading House of Leaves -- I see where the Marble Hornets crew got their ideas.

Silence of the Lambs....the ending.....in a theatre........ HE WORE A DUDES FACE FOR BILL PECOTA'S SAKES!

Jacob's Ladder
The Exorcist (really gave me the spooks as a kid)

Honorable mention:
[Rec]

WolfCreek

I really like a movie called Session 9. They filmed it inside a real abandoned mental hospital in Danvers, Massachusetts. It's a pretty slow movie and it revolves around an asbestos removal team that has to go inside this old place and obviously....remove asbestos. Well the place is just creepy. One of the guys finds an old box with a bunch of recorded sessions with a female patient with multiple personalities. I really won't go into any more detail than that, and this movie probably isn't for everyone. However I really found it to be a good scary movie.

Great movie. I bought it before viewing it and have let many friends borrow this gem. Great psychological horror flick.

Glad someone else likes it too. I heard that they've since turned that hospital into an apartment complex. Boy it must be spooky living there!

As a kid: Child's Play
As a teen: IT
Now: The World News

The original Black Christmas used to freak me out...

The Day After still touches a harrowing nerve with me, even today as an adult.

I enjoyed that movie as well.

I can't really think of a movie though that kept me up. Fire in the Sky scared the shit out of me when I was a kid....as did Nightmare on Elm Street.

These days it seems to be more about memorable moments rather than memorable movies.