Wheel of the Year is more a source for meditational study and a reference book on certain topics than a "standard text", but it gives a good sense of the pagan year for neophyte witches.
This volume is organized around the "wheel of the year," the cycle of seasons. It's an excellent source of seasonal celebrations and traditions, everything fro m winemaking to pysanky (Ukrainian decorated eggs). Each of the 12 chapters begi ns with a nature meditation and comments on the season, followed by information on different seasonal traditions.
It's always a pleasure to read a work on "nature religions" written by someone with an obvious connection to nature, even if only in the shape of a garden and/or a will to observe nature. The prose is lyrical and the illustrations clear and pretty.
Topics covered especially well include: trees and wood for the Beltane fire; brooms; thread/knot/quilting magic; seasonal rituals with "corn dollies"; making a "witches' ladder"; bread symbolism and celebration; celebrating Halloween/Samhain; garden planting and harvesting rituals and magic.
The book, however, handicapped by the lack of an index (I ended up writing one for myself). The table of contents lists in detail areas covered in the book, so one can browse if you're not inclined to build your own index.