I use a PB superflash on the rear and a flashlight attached to my bars with an old inner tube tied into a loop...
The light is a MTE "P7-D" that I bought from DealExtreme. The light is pretty good, but if I were to do it again, I'd get a Fenix l2d premium q5 light. The Fenix is just as bright to my eyes and has a more useful light pattern. Also, it runs on 2 regular AA batteries (instead of the single 18650 cell of the MTE), so you could pick up batteries at a convenience store in an emergency...and the Fenix lasts a little bit longer on the highest power setting compared to the MTE. Additionally, the Fenix is significantly smaller; small enough to use as a helmet mounted light if you chose to do so. Don't get me wrong, the MTE is a fine flashlight, I just think the Fenix is a better light.