Help me out how would you decorate this? It’s my husband’s office for a construction company. We will put a piece of artwork to the wall on the left and take down the blue shadow box above the window (do we put something new up or leave it blank). He has some more books to bring in (adding them to the shelf in the right) and I’ll probably switch to moving some books horizontally.

I guess I’m wondering if/what should go above the bookcases