I don't listen to tunes much while biking but was considering the
Slipstreamz product called the Slip. I've found a cheaper effective solution with these
Phillips headphones. I've found that I hear vehicles from behind even better than without any headphones/buds...particularly when riding into the wind. And I never need [nor want] the volume up much....and never anywhere but out in the boonies. Not to mention they keep my ears a bit warmer on cold riding days.
Oh and anything by Jeff Beck, Yardbirds, Clapton, Cream, etc