Right now my rabbit ears and dvd player are just sitting on the ledge.

If you could move unit and drywall above the fireplace, that would help, but I doubt that that unit can be moved without a professional to fix the lines. You could also look a simple cabinet that would follow the angle of the fireplace wall-doesnt have to be much and a decent carpenter could biuld one faily easily. I would avoid putting the unit in a vented opening-it would not work well.
also, the two color wall really draws your eye directly to the corner-our eyes pickup contrast very quickly, so I would repaint the colored wall. you could also paint the woodwork the sme color as the wall and then it would become more of a background element.

All great ideas. Thx William. I bought the apartment 2 years ago snd most rooms in this place have this brown color. Sigh

I agree with William about the vents on top, the mantel looks to be in good condition, I would just try to repaint the walls and see if that's enough update for you.