So we were foraging in Washington D.C. a few days ago and ran into Room and Board on 14th Street. Fantastic ideas and a really great design asthetic. We are helping a client with her living room and loved this idea: mount a wall ledge (or two) and add some favorite photos or other art. This one is pretty deep, so you have room to layer and have different things overlap.
The great thing about this is that you can constantly change your look and the way you line up your art. Take it all off and start over! Put a bunch of greeting cards or post cards on it. You'll always have a dynamic look.