I'm a big fan of Richard Dawkins' science writing (haven't been interested in his atheism stuff). His latest book, The Greatest Show on Earth, unfortunately doesn't appeal that much to me, and I can only think of a limited audience who should read it. Science and evolution afficianados should instead read The Ancestor's Tale or any other Dawkins book, instead.
I guess he felt he hadn't comprehensively addressed the evidence for evolution. You can't - Darwin had compiled too much evidence to do the comprehensive job he had planned, and it's increased exponentially ever since. If you're trying to provide a tool useful for arguments with creationists, though, I wouldn't write a narrative book at all - I'd create a manual, something that allows easy referencing and searching for various arguments, maybe based on Panda's Thumb or the countless other resources out there. Dawkins kept recommending Jerry Coyne's book, Why Evolution Is True, and maybe that's a better book for the evolution champions.
The book would be an excellent read for someone who actually takes creationism seriously, but I doubt they'll read it (or this blog post). It might also be good for Dawkins fans who've read everything else from him and want something new - he's said his next book will be a children's book on myths, so the good science will be a while before we see it again. Everyone else should find more interesting content in Ancestor's Tale.
UPDATE: maybe worth adding that Greatest Show has received pretty good reviews, so most people disagree with me.
Bonus blogging: why in heck did John Kerry have to hire a conservative that was spreading, in a stupid or deceptive fashion, extensive pro-torture propaganda? If he wanted to reach out with an affirmative action hire of a conservative, there are plenty out there still who don't believe in torture.