Anything worth reading...
...is worth reading twice. Sometimes.
When I find a book I really enjoy, I often tend to read it again later on down the road. Right now, I going through High Fidelity by Nick Hornby. It's a fantastic book, if you haven't read it. I read it...two years ago, I think. Actually, it was the spring before that. But yes. I'm reading it again, because I'm wondering if the passage of these two plus years has left me with any more...perspective on the novel. Time will tell. It always does, that rat.
Other books I've read at least a second time recreationally (i.e. not coerced by school assignments):
The Chronicles of Narnia by C.S. Lewis--I read the entire series four times when I was ten or so.
Farenheit 451 by Ray Bradbury
1984 by George Orwell
Lord of the Flies by William Golding
Generation X by Douglas Coupland
Hamlet by Shakespeare
I'm sure there's more, but I can't think of any right now. There are some that I read twice or more specifically for school, but it's your garden-variety reading list stuff.