One genre that's been around for a while, but is making huge advances right now (via the whole zombie and 2012 craze) is the survival fiction genre (ie, apocalyptic, super bug, EMP/CME, nuclear, biological, etc type end of the world stuff) which I've just started diving into as a writer, and it's actually more fun to read and write about than probably any other genre currently.
I don't know where it stands in the big picture, but I've been seeing sales of survival fiction stuff just sailing through the roof of late.