At another site I mentioned how Tiger Woods was known so widely by the one name "Tiger" and asked how many other sports stars could make the same claim. Based on input I received and my analysis, here's my list so far (though as I think about it, this thread runs dangerously close to ESPN's hideous "Who's Now?" feature). Since I didn't blog about the PGA, which Tiger won, maybe this will help fill the gap, while providing some legitimate justification.
Still Active, Nickname is Only Name Used
Tiger (Eldrick Woods) - worldwide, I suspect
Junior (Ken Griffey, Jr) - moreso with baseball fans than others
Becks (David Beckham) - elsewhere but US
Many soccer stars, particularly from Brazil. I'll add a list later.
Still Active, Given Name
Shaq (O'Neal) - short for Shaquille, but close enough to his given name to be in this category
From the Past, Nicknames
Pele (Eduardo de Nasciamentes) - the "Tiger" of his day. Internationally renowned, he took the extra step of dropping his given name altogether and replacing it with "Pele." (photo by Jeffrey Biteng)
Duke (Edwin Snider) - he shares this appellation with John "The Duke" Wayne.
From the Past, Given Names
The NBA's all-time leading scorer, he started with two names (Lew Alcindor) converted to three (Kareem Abdul Jabbar), but needed only the sky hook and one name, Kareem, to be recognized. (AllPosters.com)
Reggie (Jackson) - outsized personality overcame common name to make it his own. As cocky as the actor is on ESPN's "The Bronx is Burning", I don't think he measures up to the real thing.
Martina (Navratilova) - at least until Martina Hingis came along, but by then Martina was out of the singles limelight. Her difficult last name also encouraged first-name only references. Billie Jean (King),. Chrissie (Evert) and Steffi (Graf) also come close to making this category.
Arnie (Arnold Palmer) - He had his own army! I think that a sports fan (and many others) in the late 50s and early '60s would have recognized who "Arnie" was without a last name or sport mentioned.
Please leave any other names you can think of that should be on this list as comments.