A large number of Randonneurs go with the Schmidt hub system, and I have to admit that it casts a lot of light and seems fairly reliable.
I, however, cannot justify the cost. Up here in Canada, it would likely cost me nearly $500. In the US, I think the system goes for something like $300.
So I ride with a series of inexpensive battery lights. I use Planet Bike lights for a more "white" light - good for descents - and I use the new Cateye EL 500 for my regular light. That one lasts forever. It does give a bluish glow, which some people don't particularly like ... and the light pattern is in the shape of a cat's head which is great for hallucination purposes late into a ride ... but other than that I'm quite pleased with it.
One day, though, I would like to get that Schmidt hub.
Oh yes ... when I did the PBP, we had to go through a bike inspection where they checked our lights. So, that was fine. On the first night I was riding with some of the European people ... and their lighting systems consisted of FLASHLIGHTS taped to their forks ... dim flashlights at that!! I could hardly believe it!! But ... there you go ... another option that will actually pass a bike inspection!