The Long Tail : Why the Future of Business Is Selling Less of More by Chris Anderson
I may be slightly biased in favor of this book because Wired threw an incredibly kickass launch party for it back in July, but it really is a very well-written book. I'm not the most business-savvy person, but this was very easy to read and understand. As for the innovation of the idea, it's the sort of thing that I feel like someone else would've gotten to if Anderson hadn't. He just happens to have been the first person to put it into words.