Protecting your ears is as important as any other safety item on your checklist. Hearing damage is real and it is insidious. It is cummulative. It is time-weighted, as the higher the noise, the less time it takes to cause hearing damage. Once damage has occured, it is irreversible. Here is an article that gives good insight to why ear protection is so important while riding your motorcycle.

Here is some good reading:

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=539364

This paper mentions that most noise is helmet induced wind and vibration to the tune of 90db at 60 and 110db at 95.

Wear your earplugs!!

http://www.webbikeworld.com/motorcycle-helmets/helmet-noise.htm

This article is a good read and refers to a Windjammer helmet air curtain, and other resources.

http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=90

A good one page document.