I'd say about 60% at least of the guys in my last office listened to music when the market was slow (afternoons, etc) or whenever....now only about 2 of the 5. I've tried it...I can't really concentrate, but of course, maybe cause my playlist is all my favorite songs and I wanna sing along, lol. W/ a better chosen playlist I could probably do it during the slow times.
Lights - I disagree 100%. For me, I love having music in the background. I don't focus on it, but it's better than dead silence. Forget CNBC, Squak Box, etc.