add wood wallpaper to the kick plates of the stairs. Those rolls are expensive but you would only need one. Not practical with white treads though, it will be stuffed up from black shoe soles in no time.
Guest bath Use current towel rod; add strong shower curtain rings and make holes in baskets. Can do in both bathrooms? In our bathroom: move hand towel and cloth to other wall on hooks. In other bathroom: move Gord's towel above mine on back of door.
Make your baseboard more dramatic.add small pieces of trim to the top of existing baseboard, add a few inches and add another piece of molding. Paint the wall and trim white. This also works for crown molding too! <-- or fake a baseboard altogether