Penguin Classics, a line of classic literature traditionally published as paperbacks with useful notes for the student, have been redesigning their cover artwork for a few years as part of the "Graphics Deluxe" editions.
Paul Buckley directs the art on these new printings and has been employing some of the best contemporary graphic novel artists and modern illustrators.
Many make the odd choice of putting text or dialogue from the novel on the cover, as is the case with Joe Sacco's treatment for One Flew Over the Cuckoo's Nest by Ken Kesey. It's hard to believe such a busy cover would outlast the simpler aesthetic of a previous version, but then the point of these is to create collector's items.
The more traditional, leaner, cleaner art work best not only as design, but as eye catching art. Seth's work for The Portable Dorothy Parker is great, as is the lithograph look of Tomer Hanuka's NSFW cover of De Sade's Philosophy in the Boudoir.
One exception to the text-heavy look is Tom MacDonald's cover for a collection of Greek mythology retold by Robert Graves. MacDonald makes it look like a Golden Age comic book, and thanks to the nature of the material, it's a perfect match. Check out the wrap-around view to get the full effect.
And speaking of wrap-arounds, Rachel Sumpter actually embroidered a few covers, doing a dense mess of color and texture for The Wizard of Oz, and an impressionistic mural for Kenneth Grahame's The Wind in the Willows -- both worth studying.