Almost none. I generally feel there are simply too many good books to waste time rereading any.What are the evergreens on your bookshelf?
Here's a complete list of my exceptions:
1) "Do Androids Dream of Electric Sheep" by Philip K. Dick - This is the only novel I've read more often than twice. Basically, I reread it every couple of years, particularly after having watched Bladerunner again.
2) The "Watchmen" comic series by Alan Moore - the only comic I've thoroughly enjoyed reading since I left school.
3) "Lord of the Rings": After reading it in German, I decided to reread it in English - and I liked it much better!
4) "Ilium" by Dan Simmons: After reading it in English, I reread it in German since I'd received the sequel in German several years later.
5) "Count Zero" by Wiliam Gibson - the second part of the Neuromancer trilogy: I had originally read the trilogy in German and since they changed the novel's title I initially didn't recognize it for what it was!