Honestly, I would likely go with a solid color for the case while working with the components as accent colors. If the two options you've listed are the only options, I'd go with the White case, grey components(backplate or the fans shroud) and gold accents(likely from sleeving and/or watercooling).
One way of tackling a theme is to see the sort of components you have access to/are working with. To that affect, mind sharing your system's specs?