I have refrained from watching movies that involve exorcism, and demon possession since I have become a Christian. I believe that evil attracts evil, and by watching these types of movies, it is making myself that much more vulnerable to an attack by demonic spirits - essentially allowing them a foot in the door, if you will.
As I type this, Constantine, a movie in which Keanu Reeves plays the role of an Exorcist, is playing in the background. I feel that I SHOULD be watching this just as much as I shouldn't.
I'm praying constantly that I would not ever in my life have to deal with a demonic spirit - aside from the one I battled late last year. But regardless, there is so much peace in the fact that in the grand scheme of things it doesn't matter - the battle has already been won! Thanks be to God!