Well it seems kind of counter productive. Wearing earplugs. to lessen the noise then turn the radio up so you can hear it over the noise, and through the earplugs
I wear earbuds when I ride to block out the noise and I can still listen to music at a very low volume (first or second notch on my ipod) and still hear what is going on around me, (cars passing, etc.) just no wind.
It seems like everyone is ganging up on you, but please don't be offended. It seems everyone has different opinions from your own. The beauty of the situation is your opinion is the only one that matters when it comes to accessorizing your bike (until your accessories become a safety hazard to others of course).
I found the (near) perfect setup to be earbuds that fit tightly in your ear, ipod in my pocket or tank bag, and
this little remote to allow me to control the music if I need to (stop it when travelling through town, or at a light, etc.). You can also get one that displays track information, but I didn't think that was worth the extra money.