I didn't see so many horror movies because I don't like those kind of films that shows blood or a dead rotten body, but I love mistery movies, when you have to think about the things that are happening.
If I have to choose one film of horror I would choose The Ring. It's a very scary film, I think that the story is very original, and it have a little of mistery, too. The situation it was also scary: I was with some friends, we were sitting in a bed and everything was dark. We saw the film on the Internet and sometimes the video stopped in a suspense part, so we didn't know when it would continue. I really had a bad time!
In my opinion the worst scene, I mean, the best horror scene it's that one in the end, when the girl ghost comes out of the television and kills the boy. This is not scary at all, when I really get frightened it's when the girl founds him, in a chair which was rotated, so the girl didn't know that he was dead. Then the girl turns the chair in slow motion (that part of the scene when you've time to shout: don't turn the chair! Oh my godness don't do it!) and it appeared the dead body and it was terrible.
I couldn't find that scene, but I found the scene before that: