I'd suggest watching 'You're Next' on netflix/etc if you have it. Granted it's more of a horror/comedy with as bad as the acting is in it, but I love it either way.
Hard Candy
I Spit on Your Grave (1 and 2)
The Tortured
Insidious
Orphan
The Possession
Antisocial
American Mary
The Woman
Tucker & Dale vs Evil
The Shining
The Mist
Zombieland (more comedy than horror but zombies are always fun)
The Cabin in the Woods
The Sixth Sense
The Last House on the Left
House of Wax
Let Me In
Cube
Mama
Mirrors
The Loved Ones
Keep in mind that some of these are EXTREMELY graphic so watch at your own risk. Some are more just psychological thrillers rather than flat out horror but all are pretty decent movies and will likely creep you out a bit. I know I have more but I can't remember them all at the moment. I'm constantly watching horror movies and weeding out the good from the bad. xD Hopefully this list helps/keeps you busy for a while!