I picked up some old skullcandy icons back when i worked at staples for like $16. I busted off the head strap park so its just 2 round speakers, and slipped them into the headphones pockets on my giro revolver.. Never been happier!
I did the same with a cheapy from Walmart $10 and some plastic surgery slipped into my helmet and it's like listening to music in your car without anything in/on your ears. LOVE IT.
Skullcandy's are cheap.. but if you live in Utah and go to Parkcity the headquarters replace nearly any broken pair you hand them no questions asked.. just walk in.. hand over your broken pair, thank the man and walk out.
Maybe this is just my strong opinion... but anyone that rides with "noise cancelation headphones" is a jackass. I'm sorry, I don't care how "good" of a rider you "think" you are.. but there's always a good reason to turn the volume down just a smidge. Nothing more annoying to me than coming up behind someone and yelling "I'm on your left!!!" as I go to pass and they're completely clueless to anything around them. Maybe it hasn't happened yet but there will come a time when shit could have been easily avoided had they been able to hear LOUD noise within a ten foot radius. *end rant*