Well, I say just fiction because I'm open to it. I enjoy dark / adult fiction such as Bret Easton Ellis, Chuck Palahnuik, Hubert Selby Junior
I enjoy sci fi esque fiction, but not over the top, intergalatic missions kind of stuff. I enjoy work by Vonnegut, Daniel Keyes, H.G Wells, etc.
And finally everything by John Green.
The late Ray Bradbury.
Wrote a lot of sci-fi
(not the far-out galaxy stuff, more like alternate earth futures).
Try his short stories so you can get an idea before you start his novels.
My personal favorites:
-All Summer in a Day
-There Will Come Soft Rains