ROGER FEDERER, SWITZERLAND
One of the all-time greatest in his sport, with a record 17 Grand Slams, Federer has surprisingly never won the top prize in Olympic singles tennis. But he's made his desire for a gold medal known. "As you can imagine, with the history I have at Wimbledon, it's going to be super-exciting," Federer, 30, told the AP of the upcoming London competition. The fact that he just won at Wimbledon, on the same courts he'll be competing on for the Olympics, shouldn't hurt his chances, either.