DH and I use NiteRider TriNewts for our winter commute (smaller lights in the summer). They're crazy bright, but there are quite a few sections where our city doesn't see fit to install and maintain roadside lighting. There's also some sections with heavy traffic where smaller headlights would simply blend in. We're careful to be respectful with our brightness- keeping the lamps tipped down, shielding them if we see pedestrians squinting, etc.

I'd rather err on the side of being too bright than not bright enough.