I'm taking one highway which is two lanes, not very busy at all, and rather scenic and laid back. I'm also taking a single lane state road which is about as straight as you can get and also sparsely populated. Once I get into the busy rush hour around the city, I think I would turn down/off the music. I tend to in the car anyway so I can concentrate.
I don't know if my dad was pulling my chain, but he used to tell me, driving with headphones in was illegal. it seems now with iPhones, I see people on calls all the time, which, I suppose is better than one hand holding it. Still, I didn't know if there were any legal restrictions to using headphones while riding.
Greywolf, what kind of GPS do you have? Do most come with a music mode? I haven't bought a GPS in ages since the droids started coming with Google Map Navigation.
You're Mr. Stevens?