Memorable moments. When I created the Countdown I played around a bit with what I wanted to name the final ranking. Impact and statistics were the obvious first two, but the third one was a bit tougher to decide on. Other categories that were considered included legacy, prestige, feeling and overall (sort of a Madden rating). After considering all of this however, I realized that memorable moments are huge and important in making a player a top player.
Consider Taysom Hill. Taysom is one of the most memorable players recently for BYU because of his unique skill set and motivation.