You have so many options here. The sofa is a black elephant in an empty room - you could move it against the wall and get a couple of chairs with side table in between facing the fireplace, a large coffee table, a rug and an ottoman/ bench on the other side (by the door). Fireplace is huge (and the mantel is cluttered with frames - too many too small) - to achieve balance, add a pair of cabinets on each side with large lamps and art above it.

I would not decorate until purpose of room determined.