Thank you for your comment .. Here is rest of room. I have thought of a built shelf but not sure how to make it functional and mount a tv within

I agree with Julie, find a custom cabinet builder and have them install shelves that you can display books and perhaps some sculptures. I would consider having them build something that will hide the television when not in use. Perhaps try and incorporate the white on the fireplace mantel, make the walls flow together, even if you loose some of the space behind the television.

What about a tv wall bracket that you can manoeuvre?

Planning on putting a bracket for the tv but would like to have design to it and the tv not be so deep in niche

I actually do not have a problem with the way the tv area looks right now. The pieces go together nicely and the tv is taller than the mantle and fills the area nicely. IF I were to change one thing, I might angle it just a titch more in to the room.

If you don't go the built-in route (which is great if you can afford it and it is awesomely designed!), you could go with an expandable wood entertainment center and expand it the width of the entire space. The one I have expands wide and has display shelves in the center that are open, and cabinets on the sides with glass doors which are amazing for hiding all of the family entertainment stuff!

Do we as a society "really" need such a giant tv? Does a TV have to dominate the entire floor?

I would put a smaller TV in another or several other rooms and leave this room entirely for family. I'd put floor to ceiling book cases in and a couple of oversized reading chairs and make it a reading nook. Or put in a table for playing games on or doing homework. A little space off to the side for something "family" oriented. That space is just screaming for being made cozy!

Gotta say I am not a fan of a giant tv in the living room either. If it weren't in there, that would make great space for a desk, or bookcases for a library, perhaps with closed in cabinets below. Then, maybe the furniture could be moved into a more interesting arrangement too.

-- You might think about mounting the tv over the fireplace since the nook you have it in feels a little awkward because the seating doesn't seem to be arranged to focus on the tv. Use a bracket that swivels.

Then you could center the sofa on the tv, moving the chairs opposite the widows. If there is room along the windows, you could place a console table or other shallow piece there with some small, straight-back chairs on either side of the console or stools tucked underneath.

Build a new wall that goes from the fireplace over to the right to the hallway, producing a new storage area behind the new fireplace extended wall. This would be a great wall for a big, beautiful piece of artwork/a big, floor leaning mirror, approximately 7'x4', or an architectural fragment, etc. Install an access door for this closet in the hallway or room that is pictured in your first photo along the right edge..
[Sorry if this idea is clear as mud!]

Or, leaving the nook open, you could repurpose this old tv space into an office/homework center with a [custom] built in bookcase, or install a murphy bed for sleep-over guests, or turn it into a closet with louvered doors facing the tv room, etc.

Keep this unit/doors/woodwork the same color that already exists on the walls and crown moldings so the whole wall "reads" as one unit. If you use a dark color on the new build, the wall will be divided in half and a give-away that you added the new cabinetry, not to mention that that wall will look smaller and chopped up. You want as little visible interruption to the wall as possible. Mounting the tv over the fireplace will help keep the wall unified.

Adding a chocolate brown accent color would help add definition/drama to the space. Perhaps in the rug or paint a focal wall a rich brown [that would appear in an area rug].

I am not exactly sure from the photo how deep your TV is but you did mention wanting to wall mount it. I think you could do it on either wall but it may be nice over the fireplace. One way of doing that is using TVCoverUps. Framed artwork(including your own) or mirror(such as the one you have) adds to the room's decor with the hidden TV and Entertainment Consoles beneath.
See how EASY it really is: