In a post introducing Arts & Faith's list of the top 25 horror films of all time, Jeffrey Overstreet rightly observes that not all horror is created equal:

Many horror movies are lurid and gratuitous--even pornographic. They appeal to our baser appetites.... But horror movies can do more than just frighten us. They can ask us to move beyond terror into contemplation, where fear of separation from God becomes the beginning of wisdom.

I'm not a fan of horror films of any kind, but Overstreet's reluctance to condemn a whole genre is right on. Horror aside, I try to avoid violent movies--but I weigh this concern against how good I expect a film to be. As Martin Sheen (an outspoken pacifist who's starred in some very good violent movies) puts it in The West Wing, the problem isn't that some movies are too violent, "it's that they suck. They're terrible." I think a lot of better, more challenging films could be just as effective with a bit less explicit violence, but I take Overstreet's point: "explicit" and "gratuitous" aren't synonyms.