12. Bob and Mike Bryan
Accomplishments: Bob: 18 Grand Slam titles, 2012 Olympic gold medal; Mike: 18 Grand Slam titles, 2012 Olympic gold medal
The Bryans absolutely own doubles tennis, holding pretty much every record that exists. They have won 83 titles, including 12 majors, and took home an Olympic gold medal last summer in London for good measure. They have been ranked No. 1 in the world for a staggering 311 consecutive weeks, and were voted the ATP's Team of the Decade between 2000 and 2009. Apparently, their success can partially be attributed to the fact that they are "mirror twins" (i.e., Mike is a righty and Bob is a lefty), which gives them phenomenal court coverage. Who knew?