My solution is a $20 18650-powered flashlight (200 lumen) from DealExtreme attached to my helmet. At maximum, it is so bright that car drivers honk at me, and it can blind oncoming bicyclists. For this reason, I run it at medium unless I'm alone in pitch darkness. It is also very weather-resistant, and because it is attached to my helmet, it is never left on the bike for someone to notice a crime of opportunity. It is also much easier to read street signs when I can just point my head at them.
At best, this will be useful for the city bicyclist who rarely travels at night.