I love 'Paranormal Activity' and 'The Exorcist.' 'The Shining' is a great one too, but there's not a lot that scares me. Maybe it's because I know the other side of it, and I know how movies are made, but it takes a lot for me to get freaked out.
When I start working on a batch of tunes - like roughly 10 solid tunes - I always know there'll be another 10 to follow, because for every song I invest a lot of time in, there's another song waiting behind it.