Recs.
Updated
The Urban 350 bike headlight is a great choice for any commuter. it's very bright, has amber side cut-outs, has a USB charger, a battery level indicator, and 4 light modes.
SpecsUpdate
Pros
Pro Let's you see and be seen
The Urban 350 headlight emits 350 lumens of light in a 180 degree angle, which is bright enough to let you see and be seen, but not too bright to interfere with other drivers on the road. It has amber side cut-outs, which help drivers see you from the sides.
Pro Has good battery life, easy to keep up with the battery status
The battery will last for 12 hours in pulse mode (which is what most commuters use, since it alerts other drivers to your presence), 1.5 hours on high brightness, and 6 hours on low brightness. This headlight is charged via a micro-USB port, it takes about 5 hours until fully charged. It has a battery status indicator, that goes from green to red as the battery drains, so you don't have to guess at when it's going to run out.
Pro Very easy to mount and dismount
The Urban 350 has a reliable silicone strap, that doesn't require any tools to be mounted or dismounted. It works like a belt- the strap has multiple round holes which are hooked on a plug to keep it secure. It can fit any handlebar, won't stretch or come undone in the middle of the ride, but is easy to take off before you leave your bike.
Cons
Con Needs to be charged every day if using the brightest setting
The battery will run for about 1.5 hours on the highest setting. That's fine if you can get to a power outlet daily, but if you're out mountain biking, or travelling long distances on the road, you might need to consider using the lower brightness levels, or having a separate headlight for very long and very dark rides.