Originally Posted by CastIron

Even if the streetlights are good enough to see by consider upping your game to substantial lights. I'm a purely urban commuter (always at night one way) and run HID after upgrading from two two 5 LED lights on the front. Advantages: I now have enough light to overcome numerous other sources to make certain traffic is aware of my presence (aimed appropriately they are not blinding). I can actually see into the shadows where a hole might be or a person with nefarious intent. Both of those are serious safety considerations that have come into play a number of times. Get the best lights you can reasonably afford if you're going to be spending any amount of time commuting at night.

Observations on light sources:
Halogen: good light to see, blends in nicely. Looks like a household flashlight from a block.
LED: Really grabs the attention. Poor to see with. Excellent visibility range.
HID: Seizes the advantages of both Halogen and LED but certainly not perfect.