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.

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

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!

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

Probably the most influential book ever on marketing strategy.

You like to think that your company would succeed if it were bigger. While you're dreaming about growth, you might be missing a huge opportunity: new ways of communicating are changing how we connect with customers. These methods give small companies like yours a great advantage. You're agile, fast, and passionate; now you just have to harness that power. So put down whatever you're doing and read this book. Speak Human will help you leverage the power you already have. (And if you're a big company, it's time to think "small" and get personal.)
http://www.amazon.com/Speak-Human-Outmarket-Getting-Personal/dp/0981348203?tag=shmf01-20

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.