The scariest film so far this year I think is the Descent! It just had everything it needed to be scary.
The scariest film ever, although I don't get scarred easily, was probably Halloween, not just because of the death scenes, but the music! *eeeek!*
The Blair Witch was a crap film, it was just the thought of it that was scary!
I saw Red Eye recently too, that was very edge of your seat stuff!