Descent is a brilliant scary film, but I found the scariest parts was when you didn't see them or even know what the hell they were dealing with. The part when they did the night light and one was RIGHT behind a girl freaked me out. Then you know what you are dealing with and it only became mildly scary afterwards. Maybe I prefer the suspense.
The Descent too, I hate jumpy stuff. I went to the cinema to see The Haunting in Connecticut, almost walked out when that thing comes up against the door in the basement.
I was in florida and watched paranormal activity 3 a few weeks ago while there (and puss in boots which was amazing) and I was absolutely bricking it. Only scary film I have thought to have been scary