So I recently mounted a Fenix L1D flashlight (LED) on my helmet to supplement the Light & Motion Solo Logic (halogen) on my handlebars. I find it amazing that the flashlight set to medium (53 lumens) lights up the road much better than the Solo on low (120 lumens). The same goes with the other power settings. It takes far fewer LED lumens (1/2 or 1/3 maybe) to equal the same useful lighting from the halogen. I guess it's the whiter light??
I've been wanting a brighter main light (solo logic on high is 390 lumens) and figured I needed around 800 lumens, but now I think a 400 lumen LED light would suffice.
From now on I will always rock the handlebar/helmet light combo. The helmet light is soooo useful.