I decided to add a front light for riding, not to see but to be seen. The Knog Plug front light is light, very bright, quick to mount and dismount, and has a micro USB port for recharging. Of course, it has a variety of modes - I use one of the flasher modes which is very effective and has the longest battery life (though I have yet to run out of juice even on multi-hour rides).
One minor reservation is the silicon loop used to secure the light. While it is quick and effective, the light can move a bit when going over rough pavement