Being a (not very good) road cyclist, I'm crazy dogmatic about wearing a helmet. My own helmet. On my own head. Having crashed several times in addition to being hit by a car and fracturing my T11 last year, the very thought of climbing into the saddle without a helmet makes me more than a little barfy.
But! If you choose to not wear a helmet while riding a bike, riding a motorcycle, riding a snowboard or, in the tragic case of Natasha Richardson, skiing, it's your head to damage as you see fit. A law requiring helmets on ski slopes won't bring her back, and it should never substitute for stepping up and keeping an eye on your kids while they fly around the neighborhood on their skateboards.
I sincerely hope the Democrats don't take up the mantle of this new helmet law talk. This issue, along with other issues like video game and media censorship, are areas where liberals will be much better off borrowing from the libertarian camp.