For the commuter who won't let a little darkness spoil the ride home, there's Serfas' TSL-100 Headlight. It lights your way with 100 lumens of brightness without an external cord or battery pack. Recharging is simple and convenient too: just plug it into your computer's USB port to recharge. This great light has steady and flash modes plus high, medium and low beams, and it includes a handlebar quick-release mount.
Run time: 2-9.5 hours, depending on setting
Weight: 95 grams (with bracket)