I'll try to name them all but will undoubtedly forget some!
An American Werewolf in London
Creepshow 1 and Creepshow 2
The Others
The Amityville Horror (original and remake)
The Ring (US remake)
The Orphanage
30 Days of Night
Hellraiser
The Wicker Man (original)
The Evil Dead trilogy
Don't Look Now
The Thing
The Texas Chainsaw Masscare (original)
The Hills Have Eyes (original)
Let the Right One In
Drag Me to Hell
Unborn
Hatchet
Zombie Strippers
Alien Quadrilogy box set
Orphan
The Children
Creep
Severance
Wolf Creek
Eden Lake
The Faculty
Bones
Event Horizon
Near Dark
IT
Salem's Lot
Secret Window
The Mist
Cannibal Holocaust
Saw 1 - 3
Final Destination 1 - 3
Village of the Damned (1960 original)
Children of the Damned (1964 original)
28 Days Later and 28 Weeks Later
REC and REC 2
The Shining (Kubrick's)
Audition
Frozen
The Exorcist
The Changeling
A Nightmare on Elm Street box set (all six original movies)
Wrong Turn 2
The Sixth Sense
The Host
The Devil's Rejects
Stir of Echoes
The Reaping
Funny Games (US version)
A Tale of Two Sisters
Hansel & Gretel
Frailty
Pandorum (sci fi horror)
Resident Evil
The Blair Witch Project
The Man Who Haunted Himself
Psycho
The Birds
Wake Wood
Braindead
Rogue
Planet Terror
The Fly (1986 remake)
Brotherhood of the Wolf
Paperhouse
The Fog (original)
Switchblade Romance (aka: Haute Tension)
The Brood
Cloverfield
Seven
Interview with the Vampire
Slither
Cabin Fever
The Lost Boys
The Last House on the Left (original)
Poltergeist
The Vanishing (original)
Cube trilogy box set
I've probably forgotten a few, but racked my brains for a good 15 minutes! (I'm at work so can't check my collection)
BQ: John Carpenter's 'Village of the Damned' remake absolutely terrified me. So did 'Friday the 13th' and 'Entity'
BQ2: Possibly 'Friday the 13th'
BQ3: John Carpenter, David Cronenberg, Tobe Hooper
BQ4: The Thing and Identity (I chose one, my boyfriend chose the other!)