I've always liked white - although it is true that it suits certain cars better (e..g jag XJ) than others (e.g. a peugeot)! My favourite is pearlescent/metallic white - as seen in some lambos.
much depends on the type of car and the type of journeys its going to be used for.... e.g. a 2 seater convertible vs an estate car or city car vs long distance cruises.
Personally, I think there isnt much difference and I would rather have a petrol myself - although some diesels are very...