I heard another great I-had-a-helmet-on-and-it-saved-my-life story:
One of the messengers in Downtown Denver had to work in the gross frozen yet still wet web of streets this past storm (Dec 2006). He had the few days off of riding because the offices were shut down and there was no reason to have bike messengers running around. So back to work, ice is on the sidewalks, on lamp posts, on roads, on cars, on EVERYTHING. This guy is just feeling proud to be able to stay upright on his bike with all the ice and idiots on the road. He gets a call to a place on Broadway that has all sorts of weird architecture going on. He locks up his bike and is walking toward the front door when he gets smacked on the top of his head in an apparent death blow style chomp by an entire windows worth of sheet ice. His lump of foam in plasic saved his life while he was walking. I guess he should be glad he is comfortable in it.