I will listen to radio, tape, cd, mp3 in my car, at home, at work and if I am on a plane. I also listen to it on the PC. Of all places my favourite is on my Lucas Film THX Dolby Digital Surround Sound.
I never listen to music outside (i.e walking, jogging or hiking) for two reasons. When I am in the city I need to hear the environment so I don't get run over by a stray car or something (this happened to a freind of mine and also a neighbour - for both of them it was fatal). When I am outside of the city in the country or cottage country I actually prefer to listen to the healing sounds of nature.