I'm a musician also, and I don't listen to music in the car or on the bike.
I listen to NPR. It's engaging but not distracting.
When I want to just enjoy the ride I simply shut it off.
I work with a 20-something guy who's still young enough that music really gets him going. He likes rap. He got hit with a reckless driving charge for going something like 95 on the parkway and lost his license....
It's guys like that who shouldn't listen to music. Does it calm you and help you focus or charge you up? Depends on the person. Depends on the music.
Music I love transports me. That's dangerous when operating a vehicle. Spoken word audio doesn't affect me like that.
Thanks for the link to the plugfone. I'll have to get a set to try out. I currently use, and LOVE, the S-Plug. Similar to the plugfone silicone model but much costlier.
http://www.plugup.com