Although the statement - "Famous Athletes" is subjective a few that I think deserve mention. Feel free to add.
Baseball
Stan Musial - St Louis Cardinals
Steve Garvey- LA Dodgers/San Diego Padres
Al Kaline - Detroit Tigers
Tony Oliva - Minnesota Twins
* Micky Mantle wore #6 during his rookie season but felt to much pressure to follow Ruth #3, Gehrig #4, & DiMaggio #5. He was sent down and when he was recalled from the minors later in the season he switched to the #7.
Basketball
Bill Russell - Boston Celtics
Julius Irving (Dr. J) - Philadelphia 76ers
Walter Davis - Phoenix Suns, Denver Nuggets, & Portland Trailblazers
Hockey/Football
N/A (Although it could be argued, I don't think anyone that wore/wears the #6 would be considered "Famous.")
peter shilton is by far the most famous person to pull on a no.1 shirt. he is the most capped player in English history,with 1,000 caps. sadly, he retired in 1997
Lionel Messi in his early years with Barca
Paul Gascoigne Dwight Yorke Frederic Kanoute
The Number 9 is associated with LEGENDS. It is usually worn by strikers. Greats like Lineker, Robbie Fowler, Ronaldo, Gabriel Batusta have worn this jersey. Currently, famous names associated with the jersey are Fernando Torres and Karim Benzema.
Tobin Heath, andAlex Morgan was 17 before Tobin. Indi Cowie, Yael Averbuch, and Lori Chalupny all wore 17 for UNC
gary neville
The number 84 is not a particularly common shirt number. No player who is particularly famous has ever worn it.
Players like Ben Haim and Kaka have worn the number 22 jersey. Angel Di Maria is also a player who has worn the jersey for Benifica.
Mia Hamm
Fernando Torres
Panos Bountoulousis who plays for Seaquam Seahawks
Meow and meower
auguero does
The number 84 is not a particularly common shirt number. No player who is particularly famous has ever worn it.
Dwight Yorke for Manchester United
Patrick Viera, Cesc Fabregas, Vidic.
Johnny Torres from Wake Forest University.