There were quite a number of re-reads this year, and I think I'd have to separate them out from the rest of the new books. Otherwise, nobody would be able to stand up against Dune, for instance.
The best new novel I read this year is Jo Walton's Among Others. At once autobiographical, allegorical, and fantastical, it is written well and should make every science fiction and fantasy reader quiver with delight. It very much deserves the sweep it's made of this year's Hugo and Nebula awards.
Close runner ups include The Magician King and The Kingdom of Gods. It does seem like a great year for fantasy novels. Also close and dear to me are Ready Player One and The Spy Who Came In From The Cold.
On the non-fiction side, what a great selection of choices. The one that comes to the forefront, however, is Thinking Fast and Slow. It's a great book, and you get to skip all the Dan Ariely books if you read this one. Another surprisingly useful book is Which Comes First, Cardio or Weights?. I find myself coming back to this book (and am currently re-reading it again) over and over again. For instance, one of the points made in this book is that exercise actually keeps the telomeres in your DNA from shortening. This literally means reducing your physical age and extending your life. I think about how often I run into people (frequently women) who obsess about wrinkles and white hair but wouldn't even consider an hour a week in the gym. This book is for them (and unfortunately, most of them will never read it).
The reader's choice this year, judging from the number of books sold on Amazon.com from this blog, is The Last Lecture. The price of that book was artificially low though, so I would call Career Warfare the winner based on books sold at full price. Given the shortage of good books on politics in the office, I think there's a market out there for a software engineer-specific political guide. Unfortunately, being an incompetent office politician, I'm the last person who should write that book. If you're a good software engineer office politician and need a ghost writer, however, send me e-mail and let's talk. I guarantee that this is one book that will sell. And sell.
Unfortunately, none of the graphic novels I read this year blew me away, so I'm offering no recommendation in that category. If you can name a really good graphic novel, please let me know. I'll read it and review it for next year.
And yes, the book of the year? Among Others. It's unusual for a fiction piece to beat all the non-fiction pieces, so pick it up if you haven't already!