Best athlete in the world

The "Thorpedo" Ian Thorpe.

That's a tough one. These two come up in my mind at the moment:

Haile Gebrselassie and

I think Michael Jordan and Mary Lou Retton from gymnastics would very much be up there on the list. 

That's a tough one. I think Michael Jordan and Carl Lewis.

Micheal Jordan proved to be a very bad baseball player. Jim Thorpe lived way beyond the quarter century mark.  Therefore, based on versatility, the answer has to be Bo Jackson who once hit a home run  for the Kansas City Royals and scored a touchdown for the Oakland Raiders in the same week.