In another one of those weird coincidences, i got Why Evolution is True by Jerry Coyne from the library just a couple of days after the news about the Ardi fossil broke in Nature. While Coyne's book, of course, can't cover that fossil, it is an amazing resource for all the various lines of evidence for evolution. Right when i was in the mood to dig into some meaty science i get a great book to read!
How many lines of evidence do you want? Transitional fossils? covered! DNA evidence? Done! Seeing natural selection and gene change occurring in the here and now? Explained! Coyne even covers what "scientific theory" really means. He breaks down the various points of evolution and does cover some arguments of creationists. One of the best parts, for me, was how he explained how various weird things can be explained by or predicted from evolution but completely fall apart under intelligent design. Things like sexual dimorphisms and poor design of various body systems make no sense under creationism (basically becoming a "just because" answer) but when viewed through evolution become very clear.
This book is very readable and accessible, even if you don't have much background in science or biology. When discussing the Tiktaalik fossil (which i read about earlier this year in Your Inner Fish), Coyne relates the excitement of discovery and makes it so easy to understand. Overall, i give this a 7 and recommend it highly. If you can't remember evolution, weren't taught originally, or want more info on how to explain it to others, you really can't go wrong with this one.