I listen to music whilst cycling, but the volume on my phone is limited and doesn't have a "Destroy your hearing setting" so I find I can hear cars approaching from behind anyway.
I do however always wear a helmet and have done for the past three years. Never used to like the idea but was obliged to wear one whilst out in Oz and feel rather naked without it these days.
A complete aside, but some stupid woman stepped out in front of me cycling home this evening. She was busy chatting on her phone instead of paying attention to crossing the road. Suggested that she pays more attention and she was offended and said "Well I apologised!". Thats irrelevant you twat, are you going to apologise when your lying on the floor spurting blood everywhere because you were too stupid and engrossed in your phone to pay attention when your crossing the road
. Get back to primary school and have some lessons from...