For me .. Micheal Schumacher is great Champion and all time favorite and in cricket Sachin Tendulkar is the best.
in dependence of sport: 1. in box - Muhammad Ali 2. in football - Maradona 3. in bodybuilding - Ronnie Coleman
It depends. Most of sports men are great and they spend much time to practice. It's hard enough to decide who is the greatest of a certain sport let alone the greatest of all sports.