We’ve all read lots of business books (or been told we should). What’s your favorite? Which did you find the most helpful? What changed your thinking the most? Or kept you up at night, or made you slap your head (duh!)?

Linchpin by Seth Godin?
Career Renegade by Jonathan Fields?
Thinkertoys by Michael Michalko?
The Long Tail by Chris Anderson?

Something else? Tell us which one and why.