In 1800s-early 1900s houses, it was common to have different woods on floors ... with the degree of expensiveness declining as you went away from public areas. I lived near one house where the flooring changed from rare hardwoods (inlaid, of course) in the areas visitors would see, to good oak in the family's bedrooms and private areas, to pine planks in the servants quarters. The moldings going up the staircases declined in ornateness with each floor, too. Carved walnut became less ornate oak became plain poplar painted wainscoting as you went up. Often the lower floor's flooring was continued up a staircase, with the change taking place as you stepped onto the next floor. Or at least until the wood was out of sight of the guests ... I have seen staircases where the switch happened at the landing because the upper part of the stairs was out of sight. "The stairs go halfway up to a landing, then 180 degree turn to go up the rest of the way, if that matters. " Take some photos and spend time with an editing software: maybe light wood on the stairs would be a nice contrast, maybe not. Maybe painting the risers to match the moldings and having dark tread would look best. Or match the risers to the lower floor color and the treads to the upper floor Lots of choices and none of them are "wrong".

Just to offer another perspective....I would consider using the upstairs as your actual bedrooms. It doesn't sound like huge house, and if you use the downstairs rooms as bedrooms, the upstairs could become space that you rarely use. It might be nice to create a playroom and office space on the first floor. Not ideal to go downstairs to the bathroom, but certainly not awful, and to me it would be worth it to have a more functional, fully-utilized space. A big consideration for me would be the bathroom right off the nursery. Time goes by quickly, all of a sudden you have a toddler, who knows when the day is that he can suddenly reach the doorknob and get into the bathroom. Very dangerous. I know you don't want to do anything major, but does the layout lend itself to closing off the bathroom door to the little downstairs bedroom and creating one to the largest bedroom? Also, keep in mind that whatever you decide, it's not impossible to switch it around if things aren't working. No one likes to lug a bunch of furniture up and down stairs, but it IS possible!

@cpartist: Thanks for the image. We've previously discussed doing something similar but with an attached bathroom to effectively create a garage apartment. Unfortunately, the windows shown on the back wall are actually only skylights. If we close off the double-mulled window at the left side of the existing playroom to create a bedroom, that leaves 1 skylight for the playroom and hallway. Even with adding another skylight the areas will be dark. Also not sure about creating that bedroom without direct access to a bathroom, which forces guest/children to walk through a playroom to utilize it. The more we look at this and consider everyone's comments, the more we think our hallway plan above addresses the most needs for our family. If we, or some future buyer, needs a downstairs en-suite then that could be added without difficulty. Thoughts?

First of all, using the same flooring upstairs and in the basement greatly simplifies and unifies the interior of your house. And it allows you to select one of the colors in this flooring to use on your stairs. This, of course, raises the question of your choice of flooring for the first floor, which you have not discussed. As for using your preconception of a dark flooring for your office only in the basement, of course you could do this. Keep in mind, however, that in the photos you posted above the hue bias for the Syndey Silver Maple is yellow, while the hue bias for the dark flooring sample is either orange or red. That's just a way of saying that the two samples in the photo aren't really harmonious together. If you want a dark valued floor in your office you really need to pick a flooring much closer to the hue bias of Syndey Silver Maple. That shouldn't be hard to do. Good luck on your project.