As for pilots wearing MP3 players in an airport; There is nothing unprofessional about a uniformed pilot listening to one while seated in a gate area or at an airport restaurant. Yes, I do this. However, I won't walk down the concourse in uniform while listening to an MP3 player. I can't explain why I draw this distinction, I just do.

For those of you that think that a pilot listening to an MP3 player in public as unprofessional, do you feel the same way about a pilot walking down the concourse while on their cell phone with a hands-free kit? Some hands-free kits have stereo headphones and visually indistinguishable from MP3 player headphones. How about talking on just the phone? This can go on and on. Do you see how this discussion is almost silly?