Michael Phelps ( USA )

Michael Phelps just completed the greatest Olympic performance in history. That is (or should be) without debate. But does Phelps' dominance in Athens and Beijing put him atop the list of greatest Olympians ever?
It's too early to tell, since Phelps likely isn't finished winning Olympic medals. If he returns in 2012 at the London Games and wins, say, five more medals, then there will be no question that he should be hailed as the top Olympian of all-time. If Phelps retired tomorrow though, one could still make a compelling case on his behalf.
The naysayers claim that because Phelps is a swimmer, somehow his accomplishments aren't as impressive. (One column, ridiculously, even goes so far as to say that it's "easy to win multiple medals in swimming.") Because swimming has so many racing opportunities, they say, medals are cheapened. Rubbish.
Of the 20 men who have won the most Olympic medals, only three (Phelps, Mark Spitz and Matt Biondi) were swimmers. Gymnasts dominate the top 20. If winning swimming medals was so easy, swimmers should theoretically be all over that list.
Even if they did, though, Phelps' versatility renders that argument moot. Just because all swimming strokes take place in a pool doesn't mean they're the same. Phelps won at three different distances - 100, 200 and 400 meters -- in Beijing. It's the swimming equivalent of a runner pulling the 200, 400 and 800 triple. That's never been attempted in any Olympics, let alone accomplished.
Phelps also won golds in three different strokes, a feat made even more impressive considering he was competing in those events with stroke specialists who gear their entire training toward that one discipline. That he had to swim a staggering 17 races in eight days is also not to be overlooked.
After his extraordinary performance in Beijing, Michael Phelps earned a spot on the list of all-time Olympic greats. Four years from now, he'll likely sit alone at the top.