Decorate your walls with furniture!
You would be surprised to note that furniture is there for your room walls too! This refers to wall units. Do note that these have much more than utilitarian functionality. They can lend character to any room.
Look at the stuff that you have with you. Now make sure that the shelves are sized accordingly. In case you have large coffee table books, your wall units should be sized accordingly. You can keep your home theater or your LED TV as the centerpiece here.
Just make sure that everything looks well arranged and fits in well. Do not put in too much stuff as nothing looks worse than over-stuffed shelves. In case all your things are not fitting in, get a few other wall units for yourself; or simply stack away things in a box.
Just make sure that everything matches well. After all, your furniture needs to match well to create a sense of balance!