Rajiv Ouseph, is currently number 1 ranked British badminton player
The current highest ranked player in the WTA is Chris Evert.
Garry Kasparov is the number 1 ranked player in the world.
At the time of answering this, on the 23rd of April 2013, Mark Selby is the number one ranked snooker player.
John McEnroe
As of December 2010, Rafael Nadal is the number 1 ranked male tennis player. As of January 2011, Caroline Wozniacki is the number 1 ranked female tennis player.
Roger Federer is currently ranked the No. 2 in the world. (ATP Singles)
Women are not ranked by the ATP, but by the WTA (Women's Tennis Association). The current number one in singles is Victoria Azarenka, and in doubles it is Cara Black.
Rafael Nadal is currently ranked no.1 men's singles tennis player (2010).
Rafael Nadal is currently ranked No.1 in men's singles of the ATP tour. Followed by No. 2 Roger Federer who was the previous No.1 player.
The current number 1 male tennis player is Rafael Nadal followed by Rodger Federer and Stan Wawrinka For the womens, Serena Williams is currently ranked World No. 1
Olympic Rosters.