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.
Built-ins for office. Built ins define an entry via BHG. DIY Built-in IKEA Bookshelves: "Built-in bookcases not only add a ton of character and storage, but they really can make a small house feel so much bigger!