The last book I read was Rob Walling's Start Small, Stay Small.
The last book I read (not counting those I'm in the middle of) was Making Things Happen by Scott Berkun. It was a great book on project management, which I think is important to anyone trying to run a business. The downside to it is that if you aren't involved in programming, then much of the book is too industry specific.
Free by Chris Anderson
It tries to shed some light on the seemingly ludicrous freemium business model. I loved it.