I recently donated a design consultation with proceeds going toward the walk. This project was great fun to work on because it was for a family with young kids and the room just happened to be the family room. This is a room full of windows, comfortable furniture, and lots of organic textures. One of the challenges for the room is a single shelf mounted 10 or so inches down from the ceiling and it runs the length of the room.
The couple wants the shelf to be full without being cluttered looking. This would be a great place to display a collection and creating a collection would be a cinch. My recommendation was to paint the shelf white to match the rest of the trim in the room. I felt the best way to give the shelf a "full" look while avoiding the "hodge-podge" look would be to go with a monochromatic color theme. Placing items on the shelf in tonal whites and then sprinkling in natural textures will give the cohesive feeling of a collection. Also, this could be a place to have fun with seasonal items ie; pumpkins in the fall, pine cones and branches in the winter, seashells and driftwood in the summer, etc.