I have a friend who has a tiny powder room painted a deep chocolate brown. It's different, but it is actually very cozy. She brightened it up with warm lighting (perhaps you could put one sconce on the side wall) and a few gilt-framed prints of flowers and greenery. Unfortunately, I don't have a picture. Chocolate brown would go nicely with your countertop and floor, but you would have to change out your dark brown towels or no one would find them - ha ha ha!!

Thanks crzyktchnlady for your comments. Can you suggest a towel rod or ring that wouldn't look so dominant? I can't believe how clueless I am about the most fundamental of home decor.