I would unwrap your furniture, or adjust the uvw maps to make the wood grain run correctly on your book shelves.
Try using invisible plane lights outside the window pushing light into the room. This will help brighten up the room without the need for 'area' lights.
Add a slight blue tint to the fog colour of your table glass and reduce the fog value to 0.1, this will give you the nice colour around the edges of the table you see on the majority of glass furniture.
Keep an eye on the contrast. If the windows are totally blown out, as they are, then the light hitting the floor would be just as strong and blown out.
Also little details such as handles for the windows help add an element of realism.
Just my 2 pence, I hope some of it helps