I voted hockey, not much of a vote as anyone who has played any competitive team sports can easily figure it out. However, athletic ability is but one aspect. Until you get to about 16 or 17 years old, passion and drive are the most important. In college, you pretty much have to have 2 of the 3 (athletic, passion, proper mental control), but by the time you hits the pros, what separates the all-stars from the rest of the pros is all mental.

Hockey Goalie and Baseball pitcher, in pro sports, are the two most challenging positions of all, mostly because of the mental aspect. The most physically challenging pro team sports position is probably the rover in soccer.