Almost every book I read ends up being read at least three or four times. I'm one of those people who can't get to sleep unless I read for half an hour or so first, so everything in my apartment has been gone through lots of times. But the most dog-eared books on my shelf are:

Lord of the Rings trilogy
His Dark Materials trilogy (Philip Pullman)
Terry Pratchett's Discworld series (especially the Witches books--Wyrd Sisters, Witches Abroad and Lords & Ladies in particular)
Les Miserables (Hugo)
The Talisman (Peter Straub/Stephen King)
The Dark Tower series (Stephen King, really only the first four books...the last three were a huge letdown IMHO)
Watership Down (Adams)
A Natural History of Love (Diane Ackerman)
Careful What You Wish For (Myrlin Hermes)


OK, there are a lot more, I confess. In fact, I need a bigger bookshelf. *grin*

Molly