The black plates are so much nicer. Any car registered post 1992 here has to have white plates with the EU logo, but I often see newer cars with black plates.
I also prefer the square rear plates on cars, like the Beetle, R4 and Fiat 500.
I see the new Fiat 500 has the long rectangle at the back, unlike the original, and it doesn't look as nice. I think I would almost go to the trouble of modifying that one aspect of the car if I bought one.