i don't often film my rides, but when i do, i film descents. well, so far only 2 descents, and one featuring hay-eaters. no music, just wind and some "woohoo!"-ing.
riding with horsies in glacier national park
descent in northwest NY-holding a canon g12
eastward descent on kancamagus-holding an iphone
yes, i know 1-handing it just under 50mph going downhill is ridiculously dumb, but alas...for science!