Through research and analysis, the writer of Good to Great and his colleagues deliver a collection of findings that are very informative. It plods a little at points, but I believe it's a good read, in particular for those who are struggling a little with how to make things happen.

A product of the people at 37signals, Getting Real is a great read. Although some will argue that they skip over certain points, the author(s) present the case for lean and stripped-down operations. I loved this book and felt as though their perspectives are a must-read for any entrepreneur today.

Michael Gerber's book is a great first read for someone starting a business. Although sometimes it feels a little pedantic, it does do a good job of asking the reader to see the need for processes and systematization.

http://www.amazon.com/Art-Start-Time-Tested-Battle-Hardened-Starting/dp/1591840562

Perhaps the briefest book I've ever read (okay, Green Eggs and Ham was close), Paul Arden's book is a condensed collection of great insights and observations. It won't help you gain an MBA, but it might give you a new perspective when you're feeling in a rut.

This guy is one of the best entrepreneurial minds of our time.
http://www.amazon.com/exec/obidos/ASIN/1591842239/guykawasakico-20

Richard Branson's auto-biography. It's not a standard business book, but who said anything should be "standard" in going it on your own. Along the way, Richard's book presents some pretty wild adventures, and makes the whole thing seem like an awful lot of fun!