You see the problem is these days is that all horror movies suck ass. They're either relying on special effects, jump scares or remaking mediocre asian horrors, most of which are over-rated in the first place. They never just creep you out anymore, a truly scary film for me is one that lives in the mind...something that disturbs you, and not because it was gory.
A quick couple, I'll give you a much better list later but I'm very tired so of the couple I've watched again lately...
John Carpenter's Prince of Darkness - Creeps the fucking shit out of me, I think it's very under-rated.
70's remake of Invasion of the BodySnatchers - this movie always knocks me on my ass, I'm afraid to go up the stairs after even at my age.
Donald Sutherland, that reminds me...check out Don't Look Now! You'll wonder how it's a horror for a long while but you'll never forget it, and I'll wish until the end of my days I could get the visions of the final moment out of my head. hehe
Anyway, more later...