All Marketers Are Liars by Seth Godin
I love Seth Godin's books! Every one is full of thought provoking ideas. Even better, each
book has prompted me to do something specific that enhanced my product or marketing. Read Purple Cow and Free Prize Inside, too!
The Art of the Start by Guy Kawasaki
Guy Kawasaki is a great writer and an incredibly entertaining keynote speaker. I love his funny, straight to the point approach. In a world of empty, fluffy business books and speeches Guy always delivers something I can put to use right away. His blog is on my daily list.
You Need to Be a Little Crazy by Barry Moltz
Barry's book on "the truth about starting and growing your business"
on the blog
and I think it's a great book to read if you're thinking about entrepreneurship.