I'm most keen on unusual apocalyptic scenarios. Pontypool, Kairo and In the Mouth of Madness being perhaps my favourites. Second to those sorts are animal/monster/alien apocalypses. Occassionally I note a good traditional zombie or virus apocalypse work, but all too often I find them dreary and repetitive, and I just don't tend to agree with their negative takes on human behaviour/nature, finding them lazy and generic.

I think the most plausible apocalypses are nuclear and pollution/resource depletion based. Or some kind of crazy technical jiggery pokery. I actually have a theory that the internet may have already spawned consciousnesses from unplanned collisions of code and information. Now if something like that started taking a dim view of us, well...

I'm not a huge fan of dystopian work unless its plainly way out in the realms of science fiction/fantasy. At least, not serious dystopian work. I tend to find parallels with our times too unsettling, that is unsettling to a point that overbalances any intellectual benefits. Do love Brave New World though.