Since I have a preference for white, and more importantly because the console and bootup screen for the Dreamcast was white, I would go with that. Though, unless htere is a limit as to how mny themes you can have, you can make a light and dark theme for it. I like the theme in that last link the best.
For Sony, since this is a retro magazine site, I would go with grey, and more grey, like the iriginal PlayStation. Dark grey for banners and headers, light grey for the BG. IT reflects the colours of the original and slim models of the PSOne.