I have found the Planet Bike 1/2 watt headlight to be great as a "to-be-seen" strobe.

I have Spok lights mounted to front and rear of my winter helmet and a MEC super turtle mounted to the rear of my regular road helmet... I have been stopped by so many people who have asked where I got these lights and they do much to increase one's visibility as it puts the light source higher does not get washed out by vehicle lights.

When one is commuting through heavy traffic and taking the lane these little lights can do more than many high powered lights as they are in a place to be seen and being seen and identified as a cyclist is all important.