I just finished Game of Thrones, I couldn't put it down and had to go out and buy the A Clash of Kings as soon as I was done.

Alan Turing: The Enigma, by Andrew Hodges

Although first published in 1983, I only managed to read it in 2012.

The magicians + sequel.

I found it interesting mainly because it's a fantasy book about fantasy books.

The Black Company series by Glen Cook.

Isn't this what Goodreads is for?

http://www.goodreads.com/review/list/1039487

(not all of these are from 2012, that's just when I added most)

Thinking Fast and Slow

might be old school, but 1984 and Animal Farm by Orwell

Bring Up The Bodies