Do I judge a book by its cover? Oh heck yes, I do. I admit to being shamefacedly surface about such things, and have frequently found myself drawn into a book simply because of an eyecatching design. (Of course, not all books with a nifty cover turn out to be good books.)
Like a lot of book nerds, I'm a fan of the elegant design work of Chip Kidd, who's become the first dust-jacket superstar designer and done everything from "All The Pretty Horses" to "Naked" to "The Secret History" to "Jurassic Park". There are a lot of other cool designers out there but he's still king of the block. Kidd's style of interior book design can wear a bit thin, but when it comes to covers, he's got a magic eye. After I found out who Kidd was, I was surprised to realise several of my favorite book covers in my collection turned out to be his work. A book cover is a curious animal -- it has to include text of some sort, obviously, but it also needs a visual peg. Some covers use just text in an attractive way, some use stunning images and make the art the focus, while some create something new altogether. Like all canvases, a book cover offers unlimited potential.
A cover isn't everything, but a great one can still turn your head. For instance, I've been reading a lot of good reviews of the late Roberto Bolaño's epic novel "2666", but what finally tipped the purchase for me was this amazing-looking three-paperback box set of his huge novel, which manages to look both biblical and postmodern all at once. What a beautiful piece of work by Charlotte Strick; I'm almost afraid to ruin it by reading it.
We've pretty much lost rock album cover art as a viable design medium in the age of CDs and MP3, and most movie posters barely seem to try anymore, so it's been cool to see the humble, old-tech book step up and take its place as a fetish object. Blogs like The Book Design Review and Book Covers regularly showcase design work that just makes me go, "Yowza." Worth a thousand words and all that.