Perhaps my feelings reflect the fact that Jimmer is current, with his amazing year happening just a couple years ago.
Looking further in the past, you have to love Jim McMahon and, of course, Steve Young. Rick Barry (basketball - watched the Warriors practice at the gym located in the stake center on the Oakland temple grounds) was huge for me back in the day, as was Ricky Henderson (greatest lead-off hitter and base-stealer of all time).