My kind of thread...
When it comes to this genre, it is hard for me to pick a favorite. Horror movies used to be my only obsession.
A Nightmare On Elm Street in order: 1, 3, 7, 4, 5, 6, 2
Texas Chainsaw Massacre in order: 1, 2, 3, 4
Friday the 13th in order: 3, 4, 5, 2, 1, 8, 9, 7, 6
Halloween in order: 1, 4, 5, 2, 7, 6, 3
Hellraiser in order: 1, 2, 4, 3
Scream in order: 1, 2, 3
Child's Play in order: 4, 2, 1, 3
Leprechaun in order: 2, 3, 1, 4, 5
Alien in order: 2, 3, 1, 4
Others I like:
Return of the Living Dead
Candyman
Creepshow 1 & 2
Slumber Party Massacre
Popcorn
Night Of The Living Dead
Evil Dead 2
Tales From The Crypt (Demon Knight & Bordello of Blood)
Troll 2
Urban Legend 1 & 2
Killer Klowns From Outer Space
Wishmaster
In The Mouth of Madness
Prom Night
An American Werewolf In London
Fright Night 1 & 2
Sleepaway Camp 2
Warlock 1 & 2
Puppet Master (there are so many... haven't seen the last few)
Subspecies
Witchcraft 5 (mainly because it's erotic)
Christine
I, Madman
Dracula (old version w/ Bela)
Prince of Darkness
Elvira, Mistress of the Dark (if that counts)
The Exorcist
The Fly (Jeff Goldblum version)
Jacob's Ladder (though, not really horror)
Maximum Overdrive
Misery
Nosferatu
Pet Sematary
Poltergeist
Psycho (Hitchcock)
Blacula (saw this recently on BET)
Serial Mom (if that counts)
Silence of the Lambs
Stephen King's IT
Targets
Witchboard 1 & 2
Bad Dreams
Michael Jackson's Thriller (love it, has to be on the list)
That's all I can think of for now. There are still many that I have to see.