I never used to judge a book by its cover. I would have to say that the majority of my books were purchased for their content and not the cover design. However, since starting the pub design program, I take a much longer time to purchase a book. Not only do I look at the author and summary but I tend to review cover designs for an extensive period of time.
Below, is a redesigned book cover for Fahrenheit 451. While the older covers of the book are actually quite compelling, this redesign, I think, is phenomenal. Obviously it's not a typical design. You can actually remove the matchstick from the cover. Pretty awesome. The san serif font and color choice are very modern for such a classic novel but it works beautifully. Even the spine is made to look like the rough edge of a matchbox. In my opinion it is a wonderful design that represents the book perfectly.
I think redesigning old classics keeps them new and fresh and increases the level of interest in the books for new readers.