I guess I'll list as many horror films as I can remember having seen:
(I have a few I confess to having seen--for some reason, I haven't yet seen Dracula, The Wolf Man, The Invisible Man, Psycho or practically anything past NotLD with the exception of Carrie... Yes, that includes Jaws--I admit I'm not itching to see this one as I'm afraid of Discovery Channel specials on sharks!!!--and all of the Freddy Krueger/Michael Myers/Jason Vorhees stuff... Just haven't seen it.)
Anyway, ones I recall having seen (admittedly, some are absolutely horrendous film-making and are examples of being up at 2-3 in the morning during October or getting together with friends to watch truly horrible films like Eegah!):
I used this list to figure these out:
http://en.wikipedia.org/wiki/List_of_horror_films
1920 - Dr. Jekyll And Mr. Hyde
1922 - Nosferatu
1923 - The Hunchback Of Notre Dame
1925 - The Phantom Of The Opera
1931 - Frankenstein
1932 - Freaks
1932 - The Mummy
1935 - The Bride Of Frankenstein
1935 - The Raven
1939 - Tower Of London
1940 - The Devil Bat
1940 - The Invisible Man Returns
1940 - The Mummy's Hand
1942 - The Mummy's Tomb
1943 - Frankenstein Meets The Wolf Man
1946 - House Of Horrors
1953 - House Of Wax
1954 - Creature From the Black Lagoon
1954 - Them!
1955 - Revenge Of The Creature
1960 - The Little Shop Of Horrors
1960 - Village Of The Damned
1962 - Eegah!
1963 - The Birds
1963 - The Terror
1968 - Night Of The Living Dead
1968 - Rosemary's Baby
1970 - House Of Dark Shadows
1976 - Carrie
1977 - Exorcist II: The Heretic
1986 - Vamp
1987 - The Lost Boys
1990 - Child's Play 2
1990 - Stephen King's It
1991 - Silence Of The Lambs
1992 - Bram Stoker's Dracula
1993 - Leprechaun
1994 - Interview With The Vampire
1994 - Mary Shelley's Frankenstein
1995 - Village Of The Damned
1997 - I Know What You Did Last Summer
1998 - The Faculty
1999 - The Astronaut's Wife
1999 - Deep Blue Sea
1999 - The Haunting
1999 - Sleepy Hollow
1999 - The Rage: Carrie 2
2002 - Queen Of The Damned
2003 - Wrong Turn
2007 - Sweeney Tood: The Demon Barber Of Fleet Street (not straight horror, but it is based on a horror story--kind of a quirky horror musical)
As I said, some are quite abysmal and some are legendary classics. I've also seen significant amounts of the Night of the Living Dead remake (thanks YouTube), The Exorcist (countless clips), Jaws (countless clips), Firestarter, The Funhouse (saw a few of Elizabeth Berridge's scenes), Plan 9 From Outer Space (thanks YouTube), etc... I think I did see part of one of the A Nightmare On Elm Street films (and of course, I've seen the famous Johnny-Depp-gets-turned-into-a-bloody-geyser-in-bed scene).
Movies I have interest in seeing next are probably Dracula and The Unholy Three (might as well see some more of those Tod Browning flicks). I've seen extensive clips of Dracula, but not the whole thing.
And yeah, for horror/retro campy cheese fans, you've got to see Tim Burton's Ed Wood. Great film.