Okay, let's set one rule - only post ONE book, or ONE series if the books are tightly interdependent. For instance, Lord of the Rings trilogy books would all count together because they follow directly... Harry Potter and [insert headline here] would be 7 separate books however, because they are more independent and self-complete.
With that out of the way, okay, what book was your most favouritest of those that you read this year? It's okay if it was not released in '12, but you must have read it in this year for the first time. Re-reads don't count.
For me, the best thing I've read this year would very probably be "Pump Six and Other Stories" by Paolo Bacigalupi. (It was part of the humble e-book bundle). Very memorable and hard-hitting SF short stories, with nearly perfect length and sufficient amount of unsettling ideas... Probably wouldn't work when expanded into a proper novel (for example of a shortstory idea failing to live up in novel form, just check 'Wool omnibus' - very overhyped letdown, possibly the largest of 2012), but the threads never overstay their welcome.
What's yours?