It would be great to see a pic or two of your current space.......but from your description and current color palate, a deep colored wood floor may be just the thing to bring it all together. How high are your ceilings? You'll probably want to keep the widths of the floor boards wider rather than narrow......8" or wider is very dramatic and elegant.

As for dirt/dust showing on a dark floor, it's probably better that you know the dirt is there so it can be swept or vacuumed up, rather than being unaware that the floor is dirty.

Do you have plenty of natural light/windows throughout the space? Just want to be sure a dark floor wont make the space feel too closed in......

not too much natural light ( wish there were more ) trying to provide good lighting. thanks for your input
eightgrand