Ring trilogy
The Thing
Poltergeist
The Shining
Halloween
Alien
Hellraiser
Evil Dead 1&2
A Nightmare on Elm Street
Dawn of the Dead
The Wicker Man
The Omen
Candyman
Carrie
Videodrome
All fairly old films, except for "Ring". I think it's difficult to find anything new in horror because it's all been done before and all copied or parodied since. It took the Japanese to come up with something exceptional, but maybe that's because they're not spoon fed a constant diet of American rubbish.
I quite liked "Signs" and "The Others" but I refuse to watch anything with teenagers being chased around by CGI effects.
Can't wait to see "Alien vs Predator", mind you...