Gallery Wall / photo wall - use picture ledges to avoid drilling holes in the wall, easy to move frames around! I REALLY LOVE this idea, especially considering the amount of holes I put in the wall doing our last picture wall.
Built in idea for the dining room door! Oh how I love built ins. Ikea Shelves Into Built-in Bookcases :: I really love this. You could turn any room into a library with this idea. And you don't need ikea for it, either.