2006: Roger Federer finishes world number one for third straight year highlighted by an ATP-best 12 titles, including three Grand Slam crowns at Australia, Wimbledon and New York. Wins four more Masters. Defending champion Roger Federer, right, holds the winner's trophy with runner-up Rafael Nadal of Spain after the Men's Singles final on the Centre Court at Wimbledon, Sunday July 9, 2006. (Photo | AP)