I have a Harley Davidson 1200 custom Sportster, and one night I was out for a ride when my headlight went out. Luckily I had my Surefire E2L Outdoorsman with me. I was using it to light my way down the highway when, suddenly, I dropped it at 65 mph. I pulled over and found it, and it was still on. I couldn't believe it got dropped onto hard pavement at that speed and it was still on. The impact barely scratched the body of the light, but it broke the metal clip. So I called SureFire the next day, and they sent me a replacement clip for free. SureFire makes the strongest, most powerful flashlight I've ever seen.
See the E2L flashlight: