Son of a Witch was (in my opinion) not nearly as good as Wicked. Still worth a look, though, and if you like Gregory Maguire I'd check out Mirror, Mirror and Confessions of An Ugly Stepsister if you haven't already.

PS - I think I've read most of your fic over at Fanfiction.net (you're fabulous, by the way). If you don't mind, I'm adding you as a friend on lj (I keep track of my fic here so much easier!).