What you are describing is one of my favorite kitchen color combinations. Here's an example of why I love it so much:

And here's another one using gray instead of black:

But I think dark wood on the island would be beautiful too. I imagine something like this, but with a marble or other very light surface on the island to echo the white of the cabinets:

Or like this, but with a darker stone on the main counters:

Basically, I don't think you can go wrong either way, as long as the island is dark enough to echo the dark counters, and the island surface is light enough to echo the white cabinets.
Good luck!

Thank you so much for the great pictures and the advice. They gave me some good ideas. Thanks again!!

You are very welcome!