I would love to have the music, I think it would help me. But I am with those who say it is a safety issue. Certainly never do it on a multi-use trail. I can't think of how many times I approach a jogger who has earphones and they can't hear me when I say that I am passing. Frustrating and dangerous for both of us.
I know some people use them on the open road but I feel like I really have to hear what might be coming up behind me. I often don't catch them in my mirror.
Trek Madone 4.7 WSD
Cannondale Quick4
1969 Schwinn Collegiate, original owner
Terry Classic
Richard Feynman: “The first principle is that you must not fool yourself and you are the easiest person to fool.”