I go with in-ear monitors. Shure SE 215 headphones (or better, there are pricier models) fit inside the ear, you loop the wire over the ear and then pull the helmet on. Then you have earplugs to keep out the noise and the option to pipe in music at a moderate volume that won't annihilate your hearing over time.
You do have to keep your head on a swivel and make sure you keep your eyes open.
Riding a motorcycle without earplugs or something that does a similar job is a guaranteed trip to hearing aid land. Highway-type noise levels in a normal helmet will start accumulating damage in something like 15 minutes, and every minute after that you're on your way to the "joy" of hearing aids... http://www.hearingtestlabs.com/motorcycle.htm
In theory I might see my Jawbone Big Jambox putting out enough noise that you could hear it at speed but it certainly wouldn't be enjoyable.