I've always found book jackets terribly interesting (especially after hearing from Chip Kidd at the CPC). So much work goes into choosing the perfect photos or graphics, the right feeling of font, colors that mesh well. So many people have a say in whether they think a certain cover will make a book sell. Publishers also face the challenge of rebranding popular books when people take a new interest in them, whether a new volume comes out in a series, or a book is turned into a movie.
I love the first two versions of Gregory Maguire's Wicked. The first (with a cool circular cut-out) gives a great feeling of the magical elements of the series. The second features the poster art of the Broadway musical inspired by the book. I'm not often a fan of media tie-in covers, but this one is just graphically awesome. It also features bright green page edges, which makes it really eye-catching on bookstore displays.
One would think two was enough, but the other day I came across the third round of Wicked covers... and it seems the publisher wants to recall "Little Witch on the Prairie." Why why why??