Glad you started this thread. I was going to start one myself the other week, but alas I am too damned lazy.
http://www.dreamweaverbraiding.com/index.htm is chockful of directions for creating all sorts of braids. Some of their designs/examples border on too-intensely-Ren-Faire for my personal taste, but it's an all-around good resource.
My favorite kind of braids are not the typical loose sort, but rather braids that frame the hairline or are worked into an "updo" (for lack of a better term). To wit: