Ah, good thinking, Shep. That's what I've always wanted to do with videos, but haven't got too many opportunities. I did get to try it out with Bosshardt's War PA video, and I loved the way it turned out (Get File my Bosshardt folder to see for yourself)... But Wouter got upset at me about it, so I had to stop with the creativity.
I think Wouter, and some others, have the mindset of videos existing solely for the sake of proof. Which is of course correct, very important, etc. BUT, for a majority of the people who see them, these videos exist for entertainment purposes. It's all about the wow factor, how you can't believe people can actually do that. And with that being the case, cool background music is going to be a major factor in deciding whose videos they're going to want to watch over and over.
Speaking of which, people still IM me from time to time to tell me how much they love watching Biz's AF1 SA 1:22 (also available in Get File). So, yeah, in summary, if you're just going to slap some random mp3 in there, stick with the original sound. But if you can't do sound, or have a neat idea for some music, go for it.