I love A Guide for the Solitary Practitioner but The Idiot's Guide covers everything from string theory, discussions of different traditions, different deities, setting up your altar, casting circles, the history and ways to observe Mabon, Samhain, Yule, etc., ethics and on and on...it's very complete and well organized.
I'd be happy with any of the choices and I'm looking forward to learning and discussing the chosen book but I have to make a pitch for the Idiot's Guide..don't be put off by the title. It's very good.
I hope the closeness of the race means we get to have more than one book club selection in the future. :)