Get a dynamo wheel and a Busch & Muller CYO Premium light. The dynamo of course means you'll never run out of battery power, and the CYO doesn't waste the lumens by lighting the overhead street signs or trees. They all go where needed. It is bright and wide on the pavement and in front of you. I have yet to see a battery powered light that throws off a beam like this, even though they are spec'ed much higher. I have a Shimano 3N72 hub, but there are lighter ones, such as the Shutter Precision models. Lace it up to a decent rim and you won't notice any drag. You can always ride with a non-dynamo wheel during the day if that's what you want.

I have two 18650 powered lights, and I haven't used them since I set up my bike with the above. These lights don't come anywhere close to the CYO. I put all three on at the same time and only the CYO was visible and I had always thought they were very bright.