If you can stay awake,this makes very interesting reading. Apologies if it has been mentioned before. http://motorcycleinfo.calsci.com/Articles/MotorcyclistHelmets.html
The gist of it is that extremely stiff, extremely expensive helmets are not necessarily better at protecting our brains in real-world crashes. Cheaper helmets, built to ostensibly lower standards of impact resistance and with softer foam, may very well absorb more energy, subject our brains to lower G forces, and thus reduce injuries. The thesis is rather counter-intuitive, but still pretty convincing.
As with most protective gear, fit is more important than price. No amount of protection is any good if it's not in the right place at the time of impact.
Then there is the question of the exact circumstances of any collision and whether the wearing of anything at all on your head is going to alter the outcome in any way. The Health and Safety lobby would have us believe that if a little bit of protection is a good thing then more has to be better, only in the real world it might not be. "The Snell Foundation's position on this is that they have no proof big heads weigh more than small heads." Classic
