My initial response to a dark room would be to lighten it up as much as possible! There's something so airy and light about a bright room that just uplifts my mood. Then there are some rooms that make me second guess my opinion.
Although white kitchens are my favorite, I love a stunning balance between light and dark.
If you are in love with a dark color wall, the bedroom would be my first choice! Since you spend most of your time sleeping in here, it sets the mood perfectly and there are so many light and bright stunning bedroom sets to choose from to even it out.
Bathrooms are another great option to try it out dark colors. With the surrounding white tiles and natural light in this bathroom, adding dark cabinets and flooring doesn't bring down the mood!
If you are wanting to try it out but are unsure if you'll be happy with it, try it on one wall! Pair it was a nice neutral color and give it some time to see if it fits your space.
Who knows, you might come out with a masterpiece!