Wow... I was expecting to see a whole bunch of idiot movies written here (I know, I have high expectations of APS members) - but I was surprised to see intelligent movies....
Donnie Darko - although not scary, has an amazingly funny (very black humour) story line that I am not sure anyone knows - but it is a great movie (top 10 of all time).
The Blair Witch Project - I went to that movie with my girlfriend when it came out and I told her it was the real videos found. She couldn't sleep for three weeks afterwards. I think I even scared myself. Probably my top horror of all time.
Not so sure about the Exorcist though... it gave me goosebumps, but it never rated that highly.
The Evil Dead was so brilliant - haha.. I loved it - but... I watched it again recently and I was bitterly disappointed! I can't stand any of the follow up movies to it though...
Planet Terror is cooooool - I think you need to understand the genre to enjoy it though - but it is cool!
I haven't seen a lot of horrors recently - the ones I have, have been less than scary that's for sure.
Was it 1308? I can't even remember the name of it - I was expecting so much more from it from reading write ups.
The Grudge - worse in english... as was the other one about the video you watch, then you get a phone call and then you die within 7 days or something.. hmmmmm
Well, good horrors are like women - hard to find but when you do they turn out hell scary!