I have a simple flashing light when riding in Tokyo at night so I won't get stopped by the police. It is bright enough to not need anything bigger to see.

However, I do ride along the Arakawa river on some evenings, and for that, I bought the 3 pack of Duracell lights (300 lumens) in the picture, and zip tie one to my helmet. It points directly to where I am looking, and it is bright enough to see any obstacles in my way with plenty of time to stop or swerve. I tried connecting it with velcro to my helmet but that didn't work. Zip ties are cheap, can be taken off with a pair of scissors, and kept in a pocket or backpack easily. The lights are waterproof and pretty tough all around and I am totally happy with them. I even tried connecting two of them to my helmet, but that was too much.
For my work bike, I have a bar mount for it once my Cateye reaches the end of its service life.