What Horror movie is the scariest?

I am getting movies for Halloween.
What is the scariest movie you have ever seen?

The Exorcist

That movie scarred me for life when I was a kid. The surrealism was and still is too tough for me to swallow. I still have nightmare about the head scene.

Either "The Thing" or "Event Horizon". I can't decide which. The Thing has some of the most realest looking monsters ever & Event Horizon played mind tricks on you. Both were just terrifying when I was young. The nightmares, they haunt me even today.

Holy shit, animeholic1, I was fucking scared of Event Horizon too - talk about coincidence. That movie freaked me out because you never knew what was going to happen next, or what was real.

When that guy played that tape recording I knew that movie was going to scare me for life.

the original (which was scary) or the remake? (which was shit)
i dont really watch any scary movies. :P

EDIT: Scary Movie 1-4.
it even has 'scary' in its name xD

Mindhunters. A crime thriller especially interesting if you're a very analytical person. Although it was pretty boring when I watched it for the second time, the downside of all the surprise mindfucks.

The second, and by far the most horrorfying movie I've ever watched is... one that I can't even remember the name of. I watched it and never even dared to think about it again, and the fact that it was based on a real story didn't really help. I'm gonna do some research on it and tell you the result.

The Mothman Prophecies was also very scary.

EDIT : The Death Machine & Critters & Evil Dead 1 & 2 are all VERY good.

Look for the film "Audition"...It's Japanese.

Evil Dead is probably the movie that've made the most scared when watching it, but i was pretty young then so i don't know if it would be the same today.
But it's a damn good horror-movie, give it a try.

The Thing is one of the best horror-movies ever, so if you haven't seen it you suck, plain and simple.

I also recommend Event Horizion and Mind Hunters as others have recommended, they're pretty brilliant both of 'em.

The Blair Witch Project but only if none of you have seen it.

The Exorcist, Halloween, The Descent, Friday the 13th, The Thing, The Howling, Dawn of the Dead, Shaun of the Dead (brings some humor to the Zombie movie) and offcorse ALIEN

Japanese and other Asian horror movies will mind fuck you!

Here's some=
-The Ring
-Ju-On 1 & 2
-Shutter
-Alone.

like many of others' posted...1982 John Carpenter's The Thing...even todays special effects cannot surpass the masterly art of Rob Bottin...rumors said they're going to make a remake... :x :evil: that's sucks 8)

texas chainsaw massacre remake...its still haunting me :(

wrong turn...make sure to have amap before traveling 8)

all SAW movies...cannot watch saw 5...it got banned in my country :cry:

All old movies rock. These days majority of horror movies suck. The Thing is a fav.

The Grudge. The constant death rattles that Kayako makes always gives me goosebumps and sends chills up my spine. The Grudge 2 was meh.

Why would it be ebtter without that?
If you ask me that would've sucked ass, it's a horror movie ya know.