These aren't "best" anything books, but it feels like we're kinda slightly past that anyway, what with the number of people who've listed a number of books. Instead I thought I'd mention a couple that I hardly ever see...eh...mentioned, but which I really, really enjoyed.
Sheri S. Tepper's
The True Game (actually three short stories: King's Blood Four, Necromancer Nine and Wizard's Eleven, but available in a single volume) is a fantasy book most of the way through, although by the very, very end the classification becomes ambiguous). Very different, very original (both then and still today) and very recommended by me.
Sadly only one short story seems available as an
ebook and I can only find the omnibus in
paperback.
Also by Tepper, The Marianne Trilogy was probably the first book (also available in a single volume) I read which could be classified as urban fantasy (I think - I'm not generally concerned with genres, except to stay far, far away from paranormal romance and such crap). To quote the Kindle Edition blurb:
"When Marianne's parents died, leaving control of their fortune to her feared older brother, she struggled to make her way as a student in America - and her old home began to seem as unreal as a fairy tale, her childhood there as distant as a dream . . . Until the Magus came to claim her, and the Black Madame to destroy her, and the Manticore to hunt her down through the streets of another world - for there is magic in Marianne's blood, and magic in her soul. And in a battle fought in an everchanging world of warped time and wicked magic, it is the souls of Marianne and her family that are the ultimate prizes.".
The three volumes (Marianne, the Magus, and the Manticore; Marianne, the Madame, and the Momentary Gods; Marianne, the Matchbox, and the Malachite Mouse) are available from
Tepper's Amazon store, but the single-volume edition seems only to be available in second-hand paper at
a rather steep price.
Again very different (Tepper does different very well indeed, which is something I appreciate greatly) and very good.