Generally speaking, I don't enjoy slasher-type horror films, it's not the gore, but rather, serial killers don't give them the same sense of satisfaction as, say, a well-imagined, well-crafted monster. I don't care for torture porn, and not really a fan of the environmental horror stories, where people drown, etc. That being said, I really love JAWS, though I guess some would argue that's in the 'adventure' genre, rather than horror.
Some of the horror movies I've greatly enjoyed are: John Carpenter's The Thing (watched this many time, never gets old), Near Dark, American Werewolf in London, Silver Bullet, The Exorcist, Night of the Living Dead, Fright Night, The Babadook, The Shining, Paranormal Activity (just saw the 1st film), and Evil Dead 2. That's a few of my fav's.
I love a good monster. Cloverfield was very enjoyable, I loved those giant monsters - same goes for The Host which had a monster in it that was really different and great fun to watch just moving around, lol
I have to say that in reading horror, I really need the atmosphere feel right. They may not be horror, but some of Ray Bradbury's work captures atmosphere in such a vivid way, you are placed right in the story. King's "The Shining" did that for me. I had goosebumps reading that book! Great experience. Recently, I've had the extreme pleasure of reading several of Shirley Jackson's books and she has a lovely way with immersing her reader into the creepy world she envisioned. "The Haunting of Hill House" was really excellent.