The best books I've read this year were (no particular order):
Kameron Hurley ~ God's War (the entire scifi trilogy)
Ann Leckie ~ Ancillary Justice (scifi space opera)
Rosemary Kirstein ~ The Steerswoman (the entire series, 4 books so far). The one merits a few words: you should read it! It is nominally fantasy, but with a scifi world underneath it, as the main character slowly discovers with the power of the scientific method of inquiry. Very enjoyable read.
Laini Taylor ~ Books 2&3 of the Daughter of Smoke & Bone trilogy (dark fantasy)
Madeline Ashby ~ vN (scifi)
I didn't read nearly as much sf/f this year as any of the previous years, but these were all solid.
What about you - what are some of your favorite reads from this year?