Just what IS "wall decor"?

Do you mean where the wall cubbies/cut-outs are? If they're not too deep, I might build some bookcases in them.

We have beautiful Giant canvas prints here That could work with your lovely decor

I did shelves, and wrapped the fireplace surround with stone, which you could do something similar for your home, but making it look more like a library..

Look at the top portion of this built in I did for the same client, and think about decorating your shelves something like this, and possible closing up the bottom portion for storage of movies and equipment.

Oh, one question Cathy. What are you planning on doing with the 3 stools by the window? Are those staying there?

I tend to agree that the recesses are asking for shelving, not art. Right now, they are the sort of architectural feature that makes me ask, "What was the architect thinking?" Filled out with shelves until they are flush with the rest of the wall, I think they would make a lot more sense.