I would bring in some more texture and pattern. You have a beautiful dark floor, so to contrast it, I would look for a medium blue area rug that has a palette of colors to draw from. In addition, I think some organic textures like baskets or wood would add dimension and not make it so stiff looking.

By the way- your color scheme is very similar to my own living room, and I made the choice to bring out gold as well, which also exists in my area rug. The gold also warms up the space on a cold day.

Since your TV is in the room, I am thinking about lifestyle, and instead of a coffee table in front of the sofas, what about using an ottoman? You could also use some small side tables on either outside of the sofas that are smaller and don't take up so much space. (A gold base with glass top?)

Between the sofas in the corner, I would make sure to do a large size square table that has the ability to either have a good lamp or even a hanging one. That corner is (in my opinion) screaming for something very fun or unique to accent the arches and the center-point of the room.

Next, I would do some sort of window treatment. They don't have to close, but there is a lot of color and depth below the eye, and it's all white at the top. To have a soft blue or gold long drape that takes the eye up and enhances the arches and high ceilings could provide a full finish to the room, and would definitely put the room together.

Finally- there is a LOT of plain white walls. I would look at taking the wall behind the fireplace and painting it a darker neutral color. Something that would nicely contrast the mantel and the mirror. (I would take my queue from the area rug).

Good Luck and I'll be excited to see your room's transformation!!