I've always loved decorating with maps, especially vintage varieties. Cavallini Papers & Co. is my favorite, and I'm usually able to get one of their wall calenders after the first of the year for a fraction of the price, or some kind family member will buy me one for Christmas, like one of the above from my mother-in-law.
Maps are ideal for decorating in my opinion because their wide range of colors will match most rooms. I like for the tones to be more neutral than bright. The very first picture was a large map I got for $3 in a clearance bin. The colors were brighter than I wanted for the room so I simply painted over the whole thing with watered down cream-colored craft paint, then split is down the middle and put it two frames.
And, though it may sound cheesy, I also think maps are great to have around the house because they are always available to teach and expand minds. They help me with my poor geography skills, and if the boys and I are talking about people in another part of the world I can quickly point the location out. They bring back memories of past travels and adventures, and keeps me dreaming about ones to come.