Open Question Wednesday #16

The teen section at the library is obsessed with vampires. Not that I'm immune; in the last year or so, I've read and watched so many vampire stories that I feel anemic just thinking about it. Running under the assumption that this vampire craze will fade away or burn out in the relatively near future, here's my question for you.

What do you think the hot new theme will be? Either in sf/f, YA in particular, or across all genres?