Are you saying the railing, newel posts and balusters (spindles) are all light wood?

Yes, the end caps, rails, newel posts are all light and the spindles are white.

Yes, I would stain the railing the dark color that the wood floor grain takes on when you do the floors. Use the Zar stains. They are thick and provide more of a consistent coverage. The newel posts and caps can be painted or stained. Check out the photos on houzz to see the different approaches.

We have light oak wood banister, stairs, and all the kitchen cabinetry -- not interested in changing that - we are looking at changing the flooring to a hardwood that might complement it - a dark wood? cherry? maple? any ideas?