I don't have a true favorite, but here's a short list of ones I did think outstanding that nobody has mentioned yet.
- Something Wicked This Way Comes (Disney does nostalgic horror)
- The Fog (John Carpenter)
- Alien (yes the first WAS a horror movie)
- Poltergeist (Scared me silly with the clown doll and pool)
- Nightmare on Elm Street (The first was groundbreaking)
- The Mist (I plotzed myself with this one. The ending is is a classic headfuck too better than King's original. Can't see it again it messed me up so bad.)
- From Beyond (Lovecraft meets bondage???? Scary as hell)
- Invasion of the Body Snatchers (both 1950's and 1970's are excellent, though the 70's version IS scarier)
- Pet Semetary (you don't WANT Fluffy back after she's gone this time)
- Maximum Overdrive (Just checking to see if you paid attention. Schlocky fun)
- Lord of Illusions (another I can't see again, but is so good)
- Hellraiser (Clive Barker... you're one sick fuck... but you're good)