Single earbud, non-noise canceling, on the right (non-traffic) side. With this setup I can still hear traffic better than when I'm in my car with the windows rolled up. I have a mirror to keep track of traffic behind me, I can hear every car that overtakes me, and l get some tunes when I'm sitting at a stoplight waiting for a light change. No heavy metal, though; that stuff makes me ride like a maniac.

If a little bit of music distracts enough of your attention from operating a vehicle to make said operation unsafe, then I sincerely hope that you don't have a radio in your car.