Since half of my commutes are at night, I thought I would add some extra lights (a little neon and some ground effects).
Hopefully it will be visible enough that the motorist will actually see me for a change.
The purple lights on the bottom are just regular car ground effects lights.
I used 3 12" strips of waterproof led ground effects lights (found at any automotive or larger department store). I mounted 1 each on the chain stays and the third on the bottom bracket.
They are quite cheap, I think I paid $7.00 for 6 12" strips. There are more elaborate ground effects set ups, where you can change the light color and action of the lights, but that would involve mounting an added controller.