Good idea or no?

A part of me feels that it's best to have complete awareness of your surroundings while you're on a secluded trail. That includes soun, which would be impaired by music. especially if you're spoiled by noise cancelling ear phones like myself...

but a part of me feels it'd make the miles fly by faster. It certainly helps while i'm in the gym, anyway.

What do you guys do? yay or nay? if there are any ipod listeners, what measures do you take to ensure maximum safety?