... I happened to see a 10 minute recap of the movie 1408 (with John Cusack) that looked really good. It is based on a Stephen King novel.
In particular, it looks like someone should watch all of the alternate endings too. I do not know anything about Insidious or almost all other horror movies, but if you are in the mood for that genre and you decide against Insidious, 1408 drew my attention.