C.K.
A friend of mine did her daughter's room in black & white too. She painted three walls white, and one black. The black wall was the smallest one so the color is not too much for the room. Anything hung on the walls is framed in opposite colors. The white walls have black frames, the black walls have white frames.
To add color to the room she used rugs and throw pillows in bright colors. She has hot pink, lime green, bright yellow, and electric blue pillows. There is a large round rug in the middle of the room that is hot pink with brightly colored butterflies on it.
The room looks amazing.
It's really simple to add colors into the room so it is not just black & white. I say just have fun with it. Almost everything matches black and white.