Mat Hoffman's no handed 900 at the 2002 X Games in Philadelphia was the best X Games BMX moment. He was the first person to land a 900 way back in 1989, and still in 2001 no one was doing variations of it. No one had any clue that he was going to do it, so when he took off spinning there was this instant realization that something big was happening. Not only was it a groundbreaking move, but it was done by someone who deserved way more than he would ever get out of the X Games. Mat Hoffman was the reason why BMX existed for many of us in the dead era of the early to mid '90s. If he didn't put all his effort into riding, putting on contests, starting a company and just pushing BMX out of the dead times, then I honestly don't think BMX would be where it is today. So, for Mat to be the guy responsible for the best moment in X Games history is rightfully fitting and fully deserved.
1. Mat Hoffman, No-Handed 900, 2002 X Games in Philadelphia