I chose silver because IMO my particular model (the new Civic) looked best in it. Though it's good in black too.
I believe some colours go with some cars and some don't. I've never been a fan of white but it does look nice on a few select cars, such as the new Fiat 500. Peugeots and the VW Golf go great with black, and the Ford Focus does get away with all sorts of unconventional colours.
Not green though. Green just doesn't do it for me regardless of the model.