Two years ago I was lucky enough to read a comment here about the 4 Hour Body and how it changed someones life. I downloaded it and read it that night. Lost 50lbs. Never looked back.
This year the book that shaped my year has to be The Motivation Hacker by Nick Winter. Great read, teaches you how to motivate yourself to get shit done. Has worked really well for me.
http://www.amazon.com/The-Motivation-Hacker-Nick-Winter-eboo...