These are my favorite. Not in any particular order.
The Exorcist (when I saw this as a kid, I kept thinking, for weeks, the devil was hiding under the bed)
Alien (This one nearly gave me a stroke when the toothy snake thingy popped out of his chest)
The Thing (You never knew who was the monster)
The Abominable Dr. Phibes (One of the funniest horror movies of all time)
HellRaiser (Made me shit and have a stroke, simultaneously)
The Grudge (Produced a wee bit o' pee in my pants)
The Descent (I like how the demon thingies ate the people)
Friday The 13th
An American Werewolf in London (Ahead of it's time in terms of special effects. It was also very humorous)
The Shining (Gotta love that crazy Jack Nicholson)
Anaconda (I love it when Jon Voight gets swallowed by the big snake and then gets spat out. If you don't know what I mean, see the movie)
Queen Of The Damned (based on two of Anne Rice's "Vampire Chronicles" books)
Young Frankenstein (Funny horror movie with emphasis on "funny")
My favorite weird/horror movies. You would swear they were on acid or, at the very least, drinking heavily while these flicks were being created. When you're watching one of these films, you feel as though you're trippin' out.
House on Haunted Hill
In The Mouth Of Madness
The Serpent and The Rainbow
My favorite horror/superhero type movies:
The Blair Witch Project (It sucked, quite horribly. Very boring. It was obviously produced and directed by amateurs. I get the idea of the movie (College kids lost in the woods, film of their "spooky adventure" gets found but the kids aren't found and so on) but the shaky camera bit was too much. I got sick and sleepy watching this turd of a movie.
Saw (I thought this was the most tedious torture flick I have ever seen)
So there ya have it. If you have any ideas or comments about my lists, scare them up and offer them up to me for sacrifice. Heh heh heh.