I'm a big fan of horror, but personally I think we care too much about putting something in a genre. You should think outside the box. If we go to the movies, think about Nightmare on Elm Street. Back when the first one was released, it was really scary. We had never seen anything quite like it, so we weren't prepared for it. The same goes for Friday 13th. Forget about Jason, the endless sequels and all that. The first one is in many ways terrifying, and especially back then. It would be very easy to make bad sequels for both Elm Street and Friday 13th, and true, they quickly stopped being scary. Elm Street 3? Great movie, but we've seen it all before. Friday 13th part 4? Jason's back. Again.
But the fun thing is they didn't have to be scary any more. Freddy and Jason both became icons, so instead of being scared of them, they more or less became the fan-heroes. They are still the villains in the movies, but for the fans, they are the heroes. Friday 13th was supposed to end with the fourth (trivia: Jason was actually alive until the finale in part 4, and didn't rise from the grave until nr 6), but fans demanded his return. And what about Freddy vs Jason? The story doesn't make sense at all, but the fans demanded the movie anyway simply because they wanted their two icons to clash.
The latest books I've read are Nightmare on Elm Street: Dreamspawn and Friday 13th: Church of the Divine Psychopat, and both are brilliant. I dare say they are better than most of the movies, even. But they are not scary anymore. They have somehow trancended the whole horror genre and become something else. It's not comedy, horror, thrillers, drama, sci-fi or anything like that. I don't think they even have a genre. They just... don't need them. It's Freddy and Jason. What else do you need?
And that's the point. What you should do is focus on writing the best story possible. It doesn't matter what genre it's in. If it's scary, put it in horror. If it's not, put it in a different genre. As long as the story is good, people will want to read it.