For me its the built in earphones on my Bern helmet. They keep my ears warm, have decent sound quality, and tune most things on the mountain out except when someone gets really close and almost hits you. I guess that would be my favorite part, if I can hear someone through the music, that means there is about to be a crash. On soft days or low mountain days, just some good ole Sony Studio Pro headphones, $40 at music stores, staples, etc. Perfect sound quality, stays on my head nicely, and keeps my ears warm.
