> From: L.S.Griffiths@physics.salford.ac.uk
 >
 > Does anyone know which (if any) US state uses white letters on a 
 > black background for their license plate colors ?

If you don't mind getting eye tracks all over someone elses stuff,
AAA carries a little book which purports to picture every variation
of license plate issued by every state in the Union. Kinda fun to 
look through.