Might I suggest a more contemporary picture frame mantel with mosaic stone tile between that and your firebox? Love the near craftsman window shapes flanking the fire wall . . . use the height on both sides, / shallow shelves on one side can visually frame a swing arm for your television and give real storage on the other side.

If they are accent chairs, put them right next to FP! Pull them away when you have fire.

You could really use anything - I do support the no fire arms idea. Look at your hobbies e.g if you are into sailing maybe some Oars, cycling a brightly covered wheel rim, gardening an antique tool, antiques & collectables a brass beg warmer, music a gitar, violin or saxophone, or fishing rods etc if all else fails a massive traditional or highly decorative modern mirror which will throw the light around the room. Make it something that shows who you are & your personality. It must be a passion or somthing rhat brings you pleasure.

Depends on how you want to style it, but I think this would look lovely and make your room feel nice and cozy.