As usual I'll abstain 'cause I'm not well-versed in the horror film genre.
Y'know, though, I've never seen Altered States. It was always was of those films I was gonna see, but never did. Is it really horror?
I have seen The Devil's Backbone and it was a beautifully creepy piece of work thematically, story-wise and visually. Wonderful film.
Hostel and its ilk are not the type of horror I ever want to see. Visual hack and slay just isn't my thing. I don't mind full-on gore, but not for its own sake. (I'm aware I may be misjudging the film since I haven't seen it, but still).
I recently re-read Pet Sematary and while King can write quite well when the fit is on him, this one seems overlong. Good creeps, though.