There are not many good individual sports rivalries going these days. Team rivalries are still going strong, but not many individual ones come to mind. Tiger Woods is one of the greatest golfers of all time, but he has no one who pushes him consistently. The entire sport of boxing has fallen off, so no one much cares if there are any rivalries going on right now. Mixed Martial Arts has potential for some great ones, but that sport does not yet have the presence. The best rivalry right now would have to be in tennis: the rivalry between Men's No.1 Roger Federer and Men's No. 2 Rafael Nadal.

Two things make a great rivalry: two opponents at the top of their sport, and two opponents whose matches against each other are always entertaining. Federer and Nadal deliver on both fronts.

Federer has just been a monster the past few years. In 2006 and 2007, he won 3 of the 4 Grand Slams. Both years, the only Slam he missed was the French Open. The same situation also happened earlier this year. Federer is especially god-like on grass; he has won five Wimbledon Tournaments in a row and could win a sixth. He is also the only man to ever advance to the finals twice without dropping a set.

Nadal seems equally unbeatable on clay. He won three straight French Opens. Nadal also pushed Federer incredibly hard in last year's Wimbledon final; at times, it looked like he was going to upset the king on his home court. If there were a weakness in Nadal's game, it would have to be hard court. He has never made it past the semifinals of the Australian Open, and never past the quarters of the U.S. Open. Still, he is easily considered the second-best player in the world now and could eventually be considered the best. Ten years from now, both these men will likely be in the talk for best tennis player of all time.