I have always like kitchens with double islands as well as the combination of white cabinets with dark accents.

Have you considered doing the islands a different color (perhaps dark) than the cabinets against the wall?

Yes I have! Orginally I thought the island might be a dark grey or some other color with a beautiful wood countertop. Then white cabinets in the perimeter, some with windows, with soapstone or black honed granite countyers on the perimeter. With 2 islands I assume I would have them match? Not sure? Also with 2 different countertops I am not sure if I should make islands a color or stick with white to keep something consistent with the perimeter. Separately, am also thinking about the windows with black painted (or black iron) frames for the wall of windowed doorsa along the back.

I would keep the two islands the same color. Even with the different countertops, I would still make the islands different from the perimeter.