THIS and THIS are two of my favorites (but I can't post because of the rights being reserved, etc, etc). Annie Butterfly's entire Flickr is worth examining, but her Dreadie Adventure is especially interesting and informative. I especially love her dread shots after she got new extensions put in toward the end... really beautiful!
Lisa Bonet with some good hair, too.
I seem to really like them in a ponytail/pulled back/up, which is weird considering I am a no maintenance hairdo kinda girl, but they look so cool!