I got a Light and Motion MV Logic light. Like it fine, but decided haolgen isn't bright enough for my expanding pre-dawn riding needs, so I'm going for their NiMh Arc HD system:

http://www.bikelights.com/Products/Arc.htm#

2-3x brighter than the MV Logic system, longer battery run times. Slightly heavier battery. I'm unconcerned about an extra .5 lb. of batter weight, I'm not racing MTB's with this light.

Here's the Solo MV Logic:

http://www.bikelights.com/Products/solo_logic_mv.htm

The logic is fine, works as advertised, the cars won't miss you with it. But not quite enough illumination for the black as death country roads I frequent around here and the 30mph downhills. My wife will inherit the Solo as a dog walking light (beats the hell out of that Mag Lite flashlight she carries).

I'd love to hear feedback on bicycle lights from those with experience. The L&M Arc system seems reasonably priced for an Arc HD light, I can get it for $359 from my LBS. The Solo Logic was about $180 (I'm sure you can buy them for less).