I have a dinotte and a magicshine headlight as well as a couple of 900 lumen flashlights from deal extreme. They are all very bright and I can see the road well. However, the beam is not very focused on any of these headlights and they are blinding to oncoming riders and joggers on an MUP. I would imagine the same is true for drivers.

For my commute, I find these lights to be "overkill." I have recently started using a dynamo light that has a reflector that focuses the beam closer to the bike and has a definite cutoff that is helpful not to blind oncoming riders, joggers, or drivers. I'm carrying one of the battery powered lights as a backup, and if I need more light. The dynamo light is the Busch & Muller Lumotec IQ Cyo R Senso. It's great not to have to worry about batteries. I wouldn't recommend this light if you have a high speed commute (20+ mph.)