I reread all the time. Most books I like I have read at least twice, and my favourite books I have reread many times. I'm sure this means I'm missing out on a lot of wonderful books, but I do read a lot (the joys of commuting by train) so I've told myself it evens out...
IMO, you get so much out of rereading a book. Some books lend themselves really well to it, because your experience is so different when you know the ending. Like watching a film when you know the twist, you are looking out for clues. Plus I often think that sometimes I do speed read a little, and so it's nice to wallow in a book when I'm not rushing in any way to find out what has happened next.
Off the top of my head, my favourite books that I have reread 3/4+ times -
Gone With the Wind
Regeneration trilogy
Wuthering Heights
Pride & Prejudice
Jonathan Strange & Mr Norrell (in fact, the first time I read this book I went straight back to the first page and started again
)
Stephen King's Dark Tower series
The Good Soldier
The Handmaid's Tale
Birdsong
And ALL of the Sharpe's 
Some of them I've reread because I want to delve into the story again (Good Soldier, Handmaid's Tale) and other's I reread because I just love them (JS&MN, GWtW) it's like watching a favourite film, it's all the enjoyment and the distraction of the familiarity. I always feel I get something out of them. If it is a good book - either good 'clever' or good 'enjoyable' I think it should easily stand up to rereading. I honestly think I had read some of those Sharpe books nearly a dozen times. They're just fun.
One thing I've found interesting, rereading some books over the years, is how much my opinion of the books and the characters has changed with my own age and experience. Wuthering Heights, for example. I've always liked it, but the book gets darker and darker every time I read it. That such a young woman could write such a twisted story... But I know it's my life experiences, and my understanding of people, which makes me see more in the story each time I read it.