Originally Posted by chaadster

I'd think that because of your low road position, you'd want to get a light up as high as possible to help generate distinguishing shadows. To that end, any one of the number of high power (e.g. 900 lumens) helmet mounted, battery operated lights would be desireable. Being able to illuminate wherever you're looking is an added nicety, and can help you keep your bearings when averting your eyes from oncoming car headlights.