'Jaws' from the Penguin Horror book series by Tom Lenartowicz I'm a big fan of minimal design for book covers. Most of the letters being underwater like a shark and the top of the 'A' being out like a fin is very clever and effective.
Chipp Kidd is an awesome designer and even gave a TED talk on this jacket design. I think for multiple books (more than 3) this is a great design concept. Could you do it with more than 3? It's good design in that while being gorgeous on the shelf, it talks about the content of the book without saying a word.