Many of the latest 2 or 3 AA LEDs are bright enough to see where you're going. I used to use rechargeable halogen systems with 5w, 10w and 15w blubs but no longer feel the need.
We distribute hundreds of Smart lights, I'm not too keen on the styling or the quality but actually, and in spite of my snobbery, they really work well and are bright enough to illuminate unlit country lanes, especially in pairs, one one the verge and one on the road.
30mph off-road is a different matter mind you, that's where Nite-Suns and the like really . . . uh . . . shine.