Also, check out Silver Ravenwolf's "To Stir a Magic Cauldron" and "To Ride a Silver Broomstick" (at least I think those are the titles......)
My dad is Wiccan, and his copy of Buckland's is heavily annotated. But I would abstain from buying any so-called "Book of Shadows" or "Book of Counted Shadows" as these are traditionally created by the practicioner of things that work for him/her.
Also, check for "The Olde Crone's Booke of Wisdom" though I know that one is hard to find.
Good hunting, and may you find what you seek.