I think it is Venus or Serena or Anna Kournikova. If Anna would win more, she would definately be "It." Serena is probably the "It" Girl by winning the French Open and Wimbledon and wearing the Bodysuit!
Serena was amazing tonight on TV. Jan Michael Gambill and Donald Trump were front row watching the match which was very short. Daniela had problems returning serve and SErena overpowered her also off the ground.
We are speaking in the present. I think Martina used to be the "it" girl, but that is debatable for now. Number one she needs to win more matches and number two wear some more revealing outfits. See Venus, Anna and Serena, Pierce, Hantuchova, etc.