Just don't ask me to choose which one I liked best!
For the reader, I would recommend The Invention of Air. It is a book accessible to any who possess the love of reading and the love of learning. And it provides a novel introduction to one of my favorite subjects: open source software. My amazon.com review (linked above) explains why.
For the thinker and the doer, I would recommend Remix, the best of Lessig's work to date. I will always have a soft spot for Code and Other Laws of Cyberspace, a book that awakened me to the realities of law not unlike the way that Neo was awakened to the existence of The Matrix in the movie by the same name. But Lessig does some real heavy lifting in Remix. He goes beyond asking the questions and beyond making the arguments to a comprehensive synthesis of solutions that should speak to both the "lefties" and the "rightsists". Again, my amazon.com review (linked above) gives more detail.
But perhaps the best testimony to the quality of these books is this: though most would dread taking two back-to-back transcontinental flights, I found that I quite enjoyed the experience, having been so enriched along the journey.