zandoval 

We hash out these light threads frequently. Its a good thing as the Lights, Lumens, and Batteries have changed drastically over the past few years. I currently am having a hard time finding a decent light configurations that uses standard batteries rather than rechargeable built in's.

Ridding at night is something I rarely do. I have noted that I need at a bare minimum 300+ Lumens. I like a beam that is wide enough to include both sides of the road at least 40 to 60 meters out so 500 Lumens fits the ticket. Where I ride there is a fair amount of medium size game so I am more comfortable with a Helmet configuration. Oddly some people have difficulty with helmet lights but I guess my Spelunking days trained my body to have good proprioception with them. I use two ChiCom 500 Lumen flash lights that use AA batteries. They are strapped to the top of my helmet and are easily adjustable by moving the straps back and forth. Using two gives me more security in case of failure and illuminates both sides of the road. When not needed they are narrow enough to stick into my tool carrier.