Getting a little more advanced:
"An ABC of Witchcraft Past and Present", "Witchcraft for Tomorrow", "The Rebirth of Witchcraft", "Natural Magic" by Doreen Valiente
"Wicca", "Wicca: The Old Religion in the New Age", "Principles of Wicca", "The Magickal Life" by Vivianne Crowley
"The Study of Witchcraft: A Guidebook to Advanced Wicca" by Deborah Lipp
"Ancient Ways: Reclaiming Pagan Traditions", "Rites of Passage: The Pagan Wheel of Life", "Circles, Groves & Sanctuaries: Sacred Spaces of Today's Pagans" by Dan and Pauline Campanelli
"Bonewits's Guide to Witchcraft And Wicca", "Real Magic: An Introductory Treatise on the Basic Principles of Yellow Light", "Witchcraft: A Concise Guide or Which Witch Is Which?", and really anything by Isaac Bonewitts
"The Triumph of the Moon" by Ronald Hutton (a scholar, not a pagan)
"Drawing Down the Moon" by Margot Adler
there's a lot that's been referred to me, but most of these I've read a lot of the works by the authors, and their stuff is well-researched and all. some of it's dry, some of it's really good.
Korealia

Are you tired of all the Wicca 101 books that you find on the bookshelf?
This is NOT a Wicca 101 book.
This book is written with a casual style that is easy to read. It is very informative and touches on a lot of subjects that those who seek the path of Wicca should know. The chapters are more like guidelines, telling you thing your probably ought to know (about history, roots, anthropology, psychology, and a myriad more) but it never occured to you to learn. Not only after every chapter does it give recommended reading (and homework), she doesn't just - throw out a list of books. Each book is explained, it's Pros and Cons, and seems more meaningful than just throwing out a book list.
If you're past buying a lot of the '101' crap off of the 'new age' shelf, grab this one. It will take you further.