Glad you enjoyed it. Sick of people complaining about it.
It's a great tradition, and for civilians, I think decorum during the National Anthem should be dictated by the situation. If you're at a soldier's funeral, or a memorial day remembrance, or something of that ilk, then stand silently at attention or sing along. If you're at something that involves celebration, happiness, and the joy of being American (like a sporting event, a parade) then I think it's just as much a celebration of the Anthem to scream and cheer and go crazy for it.
I'm sure there's military people in here that will disagree, and I respect that. It's what your military upbringing was. But the point is to celebrate and recognize what the anthem represents, which is the awesomeness of the USA, and I think that in the right circumstances, cheering does that just as well, if not better, than silence.
http://www.youtube.com/watch?v=tvpxVE_kQXg