What's a book that you've read more than 3 times?
For me, every book in the Harry Potter series. I have also listened to all of them multiple times. For those people interested in audiobooks, Jim Dale reads the Harry Potter series and he is FANTASTIC!
Here is the NYPL Catalog search for Harry Potter (note that there are a LOT more entries than just the 7 books in the series!)
For those interested in checking out Jim Dale's amazing voice performance, check out the NYPL catalog here or Amazon here.