Here is a revised layout for your room. In general, there are too many shelves with stuff placed on them. I would get rid of the curio cabinet or the etagere or both.

if you are keeping all the upholstered furniture, I would find an area rug to compliment and arrange furniture on the rug in a conversational manner. rug on carpet is fine.

only bring back the 'other pieces' as necessary. EDIT!

First visually anchor the room with a large area rug which will define the seating area. Then experiment with your furniture to see whst suits your needs/funtion and preferebces. I have to agree you have too many shelves in the room. If you feel youneed to fill an empty space or wall opt for a tall plant or tree instead. Good luck.

It looks like it might be best to make an L shape with a sofa and love seat. If you need another place to sit you can easily add a chair. Below are some other layouts which might work as well.

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