While I think Megan Fox and Jessica Alba are quite attractive startlets, it seems like Wonderwoman needs to be a bit more curvy, muscular and athletic. I can not think of any definitive choice off of my head though. Beyonce comes a bit closer to the Wonderwoman archetype, but probably she is still not tall enough (Lynda Carter had to be around 5'9''-10" tall). Maybe one of the wrestling divas would qualify.