No issues with music on the trail, actually I prefer it, so long as you use your headphones. I posted a long while back about using a small mp3 speaker for the members of my group. It had become somewhat common practice for our dayhikes. However, I was met with scathing comments about intruding on everyone else's experiences, etc. I have since atoned for previous sins and no longer use any audible speakers.

To agree with previous posts, sometimes you need an extra boost to get through a late challenge at the end of the day. For me, movie soundtracks have always meshed well with hiking. Rudy, The Natural, Jurassic Park et. al.