I would go with a long mirror...something simple will work best with window situation. Good luck :)

Are you adding any window coverings? If not, then consider art as your space needs some colour/interest and a mirror would just be duplicating the windows. Here are a couple of pics to give you an idea of frame size, etc.

Contemporary Family Room · More Info

Avon Avenue · More Info

Love those windows! They provide ambient light to the room, and to any artwork above the couch as well. I would go for either two small pieces, or one larger, longer one. I've appended visuals with Magenta and Dancer (two smaller works), and Forever Yours (longer, larger). As with any artwork, go with what pleases you, because this is your room, and you'll be seeing the artwork everyday. You want something that promotes a good, happy feeling, and what creates that good, happy feeling is individual to each of us.

There is a standard frame shape called panorama .. narrow and long .. you can go to someplace like etsy or art.com and search to see what catches your eye. Lila also has some great ideas you might like. . .center whatever you buy under the middle window . .

Something Long and narrow in shape Artwork or mirror will work there.....Here's some suggestion for your wall you might like......to know more about my Art work and collections please visit my shop on Etsy website -

https://www.etsy.com/shop/PooArtGallery

***CUSTOM SIZE AVAILABLE*****