Heavy medieval fantasy, apparently xD I don't know enough about it to make it realistic and it just feels like a bother to try. On the other hand, I would like to write science fiction which is arguably even harder.
I honestly can't really think of anything I wouldn't be interested in at least attempting to write in some capacity, although there's certainly a hierarchy of things I'm comfortable with. I think the only thing I don't have any interest in ever attempting is erotic works.
I third horror. It terrifies me as it is, so I feel like writing it would be even worse. I do have a story that is horror... but it's more on the paranormal side, which is the only thing I can pretty much tolerate. It does depend on the degree of horror and such.