At the risk of skewering a sacred cow, I've always thought cousin Nick's mark was more an act of sheer bravery than any great execution of skill.
It still takes my breath away, but for different reasons to the Moorcroft, Sampi, Smith, Walker, Farmer and Bolton marks. Each of those is a graceful, acrobatic feat of well-timed brilliance. We shouldn't underestimate the courage of flying at those heights, either.
Jack's mark is an altogether different beast. There are so many aspects to it. The courage, the timing, the ride, the twist in mid-air, the size of the pack. And the moment! While it's fresh in our minds, I also reflect on the match situation, which called for someone to stand tall when the game was on the line.
Jack's mark has everything we love about Aussie Rules in one heroic act.
I think it is the greatest mark I've ever seen.