I ran acrossed an article about hearing loss, and it's relation to motorcycles, that I found very interesting. There wasn't any online availibility of the article so I did a Google, and found this:
http://www.freehearingtest.com/hia_motorcyclefacts.shtml
I would have never thought that helmet wind noise could be so damaging over the long run. I'm going to pick up a box of those foam ear plugs. I'm deaf enough already.....