Lights and reflectors... lots of it. As others have mentioned you can buy tires with reflective strips on them.
(Picture taken indoors, with a flash)
I am also a firm believer of using multiple head and tail lights. When one fails there are others to fall back to. Also I stagger the time recharging my headlights... meaning I don't charge them at the same time. This further minimizes the chance that both will lose a charge when I am commuting at night. Some pics of my commuter:
To top this off I have a Planet Bike Headlamp on my helmet and a triangular reflector I stitched on my backpack. In addition to the reflective strip on the tires I also placed white 3M reflective strips on the rims (4 each) so motorist can see the wheels rotating at night. Finally I use bright orange ankle straps.