Peter Mendelsund has quite the portfolio of book jackets. You can see the whole lot on his site or on the Book Cover Archive.
You might also enjoy:
The Book Cover Archive 
John Gall: Nabokov Covers About Courtney
Courtney is the founder of Design Work Life and Seamless Creative, a small design studio she runs with her husband Brian. She now splits her time between developing brand identities for small businesses and soaking up (and passing along) as much inspiration as she can.
