Take note from M. Design Interiors in Los Angeles that when painting a wall, you don't have to paint the whole wall the same color. In the design above for a playroom, they put grasscloth (or it could be cork board) under a chair rail to give the kids a place to post notes and their artwork. A vibrant splash of red above draws your eye up away from the collage of work, thus creating a lovely balance on the walls.
Even without a physical chair rail, you can create the illusion of one with just paint. I suggest making it at least 36" off the floor.
A more subtle tone on tone version below in yellow.
Now since this room has high ceilings, they created a boarder in paint to bring the focus of the room down towards the furniture and artwork.
The room below has no contrast paint, but since it is a children's room in their portfolio I still needed to share it with you all: