There are some on that list that I still haven't seen or can't remember. Also, I think shock needs to be defined. Some shock in how bad the twist is. Like April Fool's Day or Haute Tension. Sadly, Sleepaway Camp was ruined for me by that Starz horror special.
Right now, I would go with Seven. I've only seen it once but I couldn't believe that the bad guy won. That they actually went there with the story.
Originally Posted by Paff
I chose The Blair Witch Project.
Early in the movie, there's a lot about the legend of the Blair Witch, but unlike a lot of movies, almost all of it is BS and never comes into play later in the movie (ever notice how some throwaway scene or anecdote early in a movie always becomes a plot point later? Not just horror, but all genres. It's like, if they put it on screen, it HAS to become important some time before the end). Obviously, it's the "stand in the corner" thing that does end up being true, and the way it's filmed is perfect. There's that short bit of "wait....what's happening....oh, it's that thing the guy talked about" going on in your mind, and I've often compared it to the feeling of closing the car door even though you know you're locking your keys inside. The brain recognizes it before the body has time to react. It's certainly a shocking effect. Sadly, it doesn't work as well on subsequent viewings, but really, that applies to almost all "shock endings", doesn't it?
I need to see this again and the sequel which looked ok from the bit I caught on TV. I remember a lot of people not liking Blair Witch. I think you never actually see the witch. That was a problem I remember people talking about. But I thought it was spooky in how the witch was always messing with them. At least from what I remember.