It amazes me that with my huuuuuuuuuuuuuuuuge backlog of stuff to read, there are still books that I will grab and re-read in preference to getting through the pile.
Recently, this has been Neil Gaiman's completely fantastic "American Gods". I had just finished his new collection "Fragile Things" which contained a novella featuring the main character of "American Gods", Shadow, and it just drove me to re-read "American Gods". I believe this is the third time I've read it.
It does amaze me the things that pop on re-reading that didn't really occur to me the first go around. Neil Gaiman is amazingly subtle with his references – I completely missed the character's last name the first time, because it's only mentioned in regards to his wife. And how there is a very small cameo by Delusion, from his Sandman comic series.
Overall, though, a book has to be Pretty Damn Amazing to get a re-read with me. My library is pretty large and while every book that I keep there has a good reason to sit in its shelf-space, there's just too much waiting for me to stop and re-read everything except the REALLY good ones.
"American Gods" qualifies.
–Robert