We also have a couple maps on our collage wall in our family room. I printed a map of the United States and placed it in on a cork board so we can stick pins in the places we have visited.
Some fun places to find maps:
Free Map Collage
America Subway Art Map
And speaking of maps, we just purchased a fun leap frog puzzle map that my son loves. A fun way to get them learning more about the US and World.