Ultimately, I want it black.
It seems that the "silver" finish on m4/3 bodies these days may not be as durable (in terms of showing WEAR) as the all black ones. Today's camera finishes and build materials don't seem to come up to the bodies of years gone by. Then again, today's bodies are dated and practically "disposable" in a couple of years anyway. It's not like the old days, where a kit of mechanical Hasselblad or Mamiya MF bodies and lenses could last your entire career! The advent of electronic, micro-process controlled camera bodies has pretty much assured short-lived camera bodies these days.
Beyond questionable wear resistance, silver-ish bodies (and lenses) are more troublesome in some reflective situations (product work, architecture, etc.) and are more "eye-catching" in street photography situations, as well. For these reasons, I prefer the black ones.
The silver and black, two-toned, 'retro' look doesn't add any value, nor appeal, to me in gear acquisition, but since it is the only option for preorder from B&H, I've got one preordered until I can acquire an all black one.