I vote for espresso. Gray will look cold.

I think..............it is black and white overkill, unless you seek very high drama. jmho. But what the hell, just PAINT/ or stain the floors satin ebony and go way high drama. I would be VERY wary of a gray attempt. You won't get gray, you could end up seeing pink, and EVEN if successful the drama of high gloss black could well "turn" your gray........to blue. Trust me on that, as you see color by comparison.

I'd think long and heard about the "total" scheme and make certain you will be happy.

The most appealing of the photos above? Directly below......and a limit to the black. The view enhanced, and just enough drama.

The brown wood in the first two above? .............uh... not as much, and actually killed by added color. But of all with a wood tone floor the last one is best. It's a strict scheme for the best result in any scenario, and requires very measured, thoughtful , "discipline maximus"

I would do the floors as close to black as possible since drame is what you are going for , please just remember to get the full effect you will need another color added to the black and white mix

Silver is nice but it is not a color so IMO you still will need color and the last choice for me would be red only because that is always what is used and can often cheapen the look of a space.

i love the look til the black crown is added.... the 'complicated' crown painted white that ends up with a lot of texture shown above would be my preference.