What about mosaic tile? Lots of colors, styles, sizes, and finishes to choose from. You can also mix tiles or keep it simple and uniform - whatever you prefer! This fireplace was done in a single color of iridescent tiles, very sleek and modern! (other colors available!)

Is that a window in center above the hearth? Is rock just a facade? Looks like you have a mixture of furniture styles. Windows look more of the modern style while drapes are traditional. I would say pick one style and go with that. From the windows I'd be leaning modern/ contemporary. If the rock is just stuck on wall take it off. Replace with horizontal wood planks stained same as your door casings. No mantle. If that is a window I would either have a stained glass insert made (again using modern lines) or do a faux stain glass painting treatment to add some visual interest.

Try the TV where the sofa is now and float the sofa perpendicular to the fireplace where you currently have the big chair. Perhaps the big chair can then go where the TV was for a quiet spot for one. Or even better, pull the loveseat off the wall and put the big chair to its left flanking the fireplace.

Is your stone veneer to be laid on a slope? I would want to see an example of that beforehand. The stones in a sloped wall are still set horizontally, but the veneer will have joints that look skewed if laid sloped so it could look quite odd.