When I bike, I almost always wear a helmet. When I ski (or least when I used to ski) I never wore a helmet. This week's death of actress Natasha Richardson from head injuries sustained in a fall while skiing have re-ignited debate over wearing helmets while skiing. A full summary of the issue can be found here. My own two cents worth: Design a ski helmet with extra insulation for keeping my head warm, and it's on my head in a second. What's your opinion on skiing with or without a helmet?