Paranormal Activity the first and second scared the crap out of me! I couldn't sleep for days... There is also a third in the making coming out this October...
The few off the top of my head...
Texas Chainsaw Massacre
The Last House on the Left
Kiss the Girls
The Shining
Have you seen the preview for Insidious?
Here is a link:
Insidious - The Movie
It looks SUPER creepy... I will admit really excited
