I've just added some lighting to my bike helmet to help me be seen better by automobiles. It consists of a Coast 1W Luxeon headlight powered by 3 AAA batteries. I've also added a Planet Bike Superflash taillight which I've mounted to my helmet instead of the bike. I've got two other lights that I plan on mounting on my battery pack and on the rear rack. I needed something small and light, yet powerful enough to not make me feel odd about the extra weight on top and put out a ton of light. This seems to fill the bill.
I've posted a video here.