HIGH TENSION IS <3. 100% agree with that one. I also think Feast is one, and Hatchet. I think those as cult classics though so maybe I'm wrong. :p Feast is awesome though.
umm i would have to say:
Maybe
Cabin Fever - it is awsome!(but i have to say at a few parts it was stupid!)
The Mist
The Descent - its a classic! so scary!
Valentine - Love this movie sooooooooooo much!!!!
Stay Alive
Joy Ride - Love this movie!
Cry Wolf