Have you ever thought about floating shelves? I think pairing a few floating shelves together would look great and would free up space in your living room. I really like the Eugene floating shelf from Bryght and I think it would compliment your existing pieces. http://www.bryght.com/product/160/eugene-cocoa-shelf

Two matching mini-chandeliers could work, but you have a vent and other holes in the ceiling and would have to work around them. If you can enclose a couple of the holes, you could place each small chandelier an equal distance from the center of the ceiling as it corresponds to the center of the table. I would suggest a large, square framed mirror over the fireplace and a large tapestry or other form of wall art on the back wall. By having two chandeliers, the wall art could be seen between them instead of being blocked by a single light fixture.There is a lot of plain space, and white-painted bead board wainscoting could break up the large, plain space and bring a different texture and color to the room. A solid-color area rug inspired by a color in the wall art or tapestry could help tie the color scheme together.

I would take away those top arches and have builtins either side of fireplace, have the tv placed on a shelf on the built in, like in the pics, you don't have to have it above the fireplace, if room is small it will feel like it's coming at you lol. Panel above fireplace and hang some artwork or a nice mirror. Quiet like the builtins with the back wall painted

Hello Monika, I must say that concrete wall is fantastic! I see a large planter with a large leaved plant there.. I like Jonathan's idea, off white or shades of cream for the remaining walls and ceiling or even a subtle stone colour.. Then we need to talk textures! I think the sofa could work if you move it out a bit from the wall and layer it up with throws and add a couple of lovely cushions.. Warm woods would be nice too to balance the room.. Have you considered adding concrete to other areas of the home? There are some fantastic concrete chairs available both as a chair and bar stool.. Could be fabulous to compliment this room.. Cox and Cox did some pendant lights that were concrete with a warm edge detail.. You could create your own arrangement with a 5 wire ceiling rose and hooks.. A glass topped coffee table could be nice too.. Have a look at eBay or vintage shops.. Oh and one more thing... You can if you like the concrete wall find wallpaper for another room say that resembles what you have in the living room or even marble! It's fabulous and a feature you want to make the most out of! :))