Well, since you asked :), let me plug my own book that came out in July:
The Web Startup Success Guide (http://www.amazon.com/Web-Startup-Success-Guide/dp/1430219858 )
The publisher, Apress, makes Chapter 6: Social Media and your Startup available free at: http://apress.com/book/view/1430219858
For me hands down it's Guy Kawasaki's book "Reality Check". It gives an excellent, easy to digest overview of all things startup. From there you can dive into great books taking you deeper into any particular area. But this gives a great overview.
Hands down, Bo Peabody's "Lucky or Smart". This book is rocket fuel for the serial entrepreneur.
I loved it so much, I wrote this review.
Sorry got to go two answers on you. Art of the Start is good at getting you motivated and confident around an idea and E Myth is excellent in getting you focused on being a smart and effective business owner. Some of the other books are decent, but I prefer those that closer to entrpreneurship and making it happen. You should be reading Harvard Business Review & Inc magazine as well. Those are awesome real-time lessons in success and failure and will get the fire going and your brain working overtime. Good luck.
Even though it's not explicitly about startup live and starting a business I would recommend getting "The Black Swan, The impact of the highly improbable ". I've found it to be an interesting read and quite motivating.
(Note I'm using the author's Amazon link as found on his website.)
Uhmn, I'm late to this party.
A off-beat and to some perhaps provocative choice: "Startup: A Silicon Valley Adventure " by Jerry Kaplan. It details life on the inside of GO, a venture capital backed startup with huge ambitions. It has a sombre, sad tone most of the time -- GO computer went bankrupt. The book begins with the bankruptcy auction, and then goes on to detail the journey.
If you after reading this book still think "I want to try!", then you're truly an entrepreneur at heart.
And you're motivated to prep before launching, i.e. read some of the other fine books already mentioned here.