What about built-ins?

first of all, how big is the ledge above the fireplace?

then my suggestion would be maybe a wall mounted tv set.

I think you should definitely mount a TV, but then build a shelf around it. (You might to to build the shelf first). If you don't want to go through all that trouble, you could also find some really wicked artwork to put up.

my thoughts exactly or even pictures of friends and family, or as my family calls it the wall of shame, lol.

Very long shelves that go the full width of the wall. If you could use this metal shelves that would look pretty awesome.

Thank you for the comments, and the mockup Mary! I should have given the dimensions - the ledge is about 3 feet deep and about 5 feet off the ground. I should have also mentioned that the tv is on another wall - it would have had to be hung too high to be on this wall (by the time it cleared the ledge).

Wicked artwork was our thought too, but figuring out dimensions is tough, considering even big pieces look dwarfed up there. I love the shelving idea, maybe I will ride that train.

Maybe even a combo of cabinets and artwork? For instance closing up the spaces under the shelf beside the fireplace with built-in cabinets and then using long strip ledges above to rest a variety of different sized art pieces.

Super sized art on the wall above the mantel can stretch across the entire wall. Very big sculpture can sit on the deep mantel. Built-in under the mantel - perhaps filling one side with a very large TV and installing shelves like the mantle and in the same material on the other side. Another option would be to replicate the four windows above with matching square mirrors marching from the mantel to the windows. Then replace the fan with a huge contemporary chandelier that will be reflected in the mirrors.