I always love seeing the covers that a designer went through before arriving at a final product. For how long the process can be and how many different designs can be considered, it always surprises me when I see tacky covers on bookstore shelves. I'm also surprised when I see the covers that didn't make it that I think are fantastic.
The New York Times posted this little collection of the "Book Covers That Got Away" in their Sunday Book Review. I think there are some really great ones in the bunch.
Some of my favorites: