How do I decorate over TV and fireplace with double arch?

I would actually cover them up, put the tv centered there and make shelves where the tv is .. maybe put doors over it and put cd's or dvd's in there. that is too busy of an area for me...

I actually did a version of Deb’s idea. My layout is almost identical to yours only my arched area is open kitchen/dining room to living room allowing some great eastern light in. So I did move my TV up to 1 arch and a large plant to the other. The cavern where the TV was became wine storage. I’m still not over whelmed by it but it’s less offensive to me and so far I’ve only spent about $15.00

We hung a vintage stained glass piece in a similar opening in our previous home. Son built a wood frame around the piece, then hung from eye bolts into top of arch. You could even have a piece made to fit your arched area if you wish.

I agree with suggestions to make one area dominant. You have a very awkward situation.

I would add doors and cover them with fabric. CHoose something pretty that coordinates with the room in a pattern or a solid that matches the paint and fades away.