Just like the photo magazines, it's equally as hard to pick good books as well. Which ones have made a difference in the way you shoot/work, or just enjoyed reading in general?
Photographically Speaking: A Deeper Look at Creating Stronger Images by David DuChemin. Made me learn to think thrice before pressing the shutter.
For the entertainment, The Moment It Clicks: Photography Secrets from One of the World's Top Shooters by Joe McNally.
I'm currently reading Real World Image Sharpening with Adobe Photoshop, Camera Raw, and Lightroom (2nd Edition) by Bruce Fraser and Jeff Schewe. Not about photography, but wow it does make a difference to how your printed photos look. As much as we love shooting, you shouldn't keep 'em stored forever in your PC you know. You've got to show it around.