So far, I've got two lights on my helmet: a Planet Bike Superflash rear blinking LED light and a front mounted Coast 1W LED head light. On the front of the bike is the Magic Shine HA-III P7 900 lumen headlight. On the rear is a cheap Bell tail ight which is why I'm building "The Blinder."
The Blinder is 3 high powered red LEDs mounted in it's own case that puts out a brilliant amount of light. The driver circuitry will produce 6 patterns and use a LiFePO4 3.6V 5 AH battery pack. The three LEDs and one driver board look like this now.
Eventually, they will be mounted inside a small waterproof housing pointed to the back. That should keep drivers away! I may also mount three facing in different directions since each one is bright enough to be seen easily all by itself. With 3 pointing in different directions, I increase my chances of being seen.