Contestant No. Seven: Serena Williams

I was going to go with Maria Sharapova on this one, and I'm willing to listen to arguments that I made the incorrect decision, but I'm just so mightily impressed with Serena Williams that I felt it would be quite remiss of me not to include her. She was 17 years old when she won her first Grand Slam singles title at the U.S. Open in 1999, and she has continued to be dominant since, winning the French Open and Wimbledon in 2002 and the Australian Open in 2003 and 2005. And that's not even all of them. Not to mention that she won many of these titles at the expense of sister Venus (who, to her credit, just won Wimbledon), from whom she stole the No. 1 rank. I don't think I'm alone in saying that Venus and Serena have completely altered the game of women's tennis forever, I think Serena more so than Venus, even if Venus did come first. The level of athleticism she displays and the aggressiveness of her game basically demand that opponents attempt to match them. Serena is a catalyst for progress in both the perception of women's sports and in the sports themselves.