I'd suggest dark red curtains if you need curtains at all -- the windows are beautiful as they are, and I'm not sure whether some kind of blind might not give you the ability to darken the room when you want to. On the wall, if you are real fans of any movies or TV shows, three big posters would be fun. Otherwise, I would still suggest using three pieces of art there of that size, all equal in size and somehow relating to each other. Three floral works, or three works in the same style, perhaps. I think a large plain textured rug in a light neutral from one of the cushion fabrics would tie the space together well. You might also consider a lovely low coffee table on the rug to lay out your snacks and drinks for serious media nights.

A combination of Offwhite, Beige Upholstery and dark shades of wood would look good. Provided you keep the wood minimal . The floor can also be a similar shade of wood . Remember whatever you do, make it look rich and elegant, only then will you be able to pull this look off. I am assuming the your ceiling is considerably high as well. Paint the walls and ceiling in offwhite shades with only the feature wall grey

Hi there! You can use beige tones- they go really well with brown if you add a hint of blue accent on. Also grey walls go well too (depends on the type of sofa you have- would be great if you can share pictures of your furniture here)!

if three parts of the wall is painted with the colour suggested (grazing land) can one part be a bit brighter colour (not very much bright but average) if you can suggest so.