I don't re-read books largely because I don't read fiction, and haven't since my college days. I know I've read the first two cycles of Thomas Covenant twice, several of Anne McCaffrey's dragon books twice, and Ursula K Le Guin's Earthsea saga twice. I recently discovered that there is a third Thomas Covenant cycle, which I have, but it's been so long since I read the first two cycles, that I'm thinking of starting over again.
I'm not much of a reader, and it's fairly common that I have 2-4 nonfiction books to read each month for various book clubs, so re-reading is just far removed from my practical day-to-day reading demands.
If I had the time, and a supportive club, I'd like to spend time reading the classics. I'm sure there's a few that I'd read more than once. In my younger days, I read mostly science fiction and fantasy. Some works in those genres bear re-reading, but more often than not, such books are entirely disposable.