I very rarely re-read a book, and if I do accidentally start one I've already read I quit as soon as I realize. There's something about knowing what's going to happen takes all the fun out of it. I guess I'm the same with movies; I'll very seldom re-watch a movie unless it's an exceptionally good "Classic" I haven't seen for a while.
The one notable exception is I recently re-read Bryce Courtenay's Power of One. It's the concensus among several family members that, if you like inspirational books, this is one of the best. It was thoroughly enjoyable (although I must add that apart from a few key scenes, I'd forgotten most of it!)