As a brief corrective to the last post's whinge, here's a Graphic Classics cover that is, I think, absolutely perfect. It's by the Canadian comics writer and artist Seth (real name Gregory Gallant--what's with these guys and their first-name-only pseudonyms?), and it's for The Portable Dorothy Parker.
And here are the front and back flaps.
As always, click for all the wonderful detail.
So what makes this a success, in contrast with the Jason/Kerouac cover? Without compromising his style, Seth has designed something entirely appropriate to the writer and the era he is covering. It incorporates examples of her work and style, and manages a number of clever, witty flourishes. It has been done with obvious affection for Parker, but with a clear-eyed vision of her flaws as well. It is, quite frankly, one of the best examples of cover design I've seen.