Well, I guess you need to find out what's important to you and then take it from there. I would recommend "The Personal MBA" by Josh Kaufman. Before you run away in terror, it's not really a business book. Sure, it covers some business topics, but not in great detail. The idea behind this book is to briefly outline most concepts and principles that you'll encounter in a business setting. Each "topic" is about 1 page long, covering principles ranging from sales, marketing and finance through to leadership, management, psychology and personal development. The end result is a basic overview of just about topic you may encounter in your career. Each topic has a number of references which can be followed if you desire. I found this book quite interesting because it gave me some insight into the what the psychopaths running the company I work for are trying to achieve. It also gave me a starting point to further investigate a number of other topics.
Read this book to find out what other books you need to read.
Apart from that, I would also recommend:
Team Geek - Fitzpatrick, Collins-Sussman (really good book!)
Rework - 37 Signals
Being Geek - Michael Lopp (a lot of fluff in this one though)
Lean Startup - Eric Ries (if you're thinking of going it alone)