Leather sofas can really dominate the room and can give an overall cold feeling. I would add some earthy elements, like a wood coffee table with glass or metal. Go to Restoration Hardware's website and look at their sofa room scenes. And I'm sorry I think the art is too harsh for the room. That's all your eye goes to in the room. too overpowering. I would look for something softer or maybe a cool mirror and I would add color to the room with pillows and some colorful lamps. I also think woven blinds would look great. They add warmth and give a finished look. The color of your window treatments should contrast your wall color a bit, not match it or else it starts to look generic and blah.. You have warm walls, warm floors and the woven blinds, like Hunter Douglas brand would pull it all together for you.

Any photos of existing furniture or the space?

Gray comes to mind but I would get what you love and repaint if you have to.

11' across x 14' can be a decent conversation zone. You have a nice window without too many privacy issues - good natural light, nice view of tropical foliage. The higher ceilings seem to be one of the things that will help the room feel larger - here's a completely different approach for you to consider . . I would instead make the beam a feature - wrap it in stained wood boards (that match or just a 1/2 tone darker than your entry doors) to make it seem a real beam - the small beam that comes out to meet it might be painted black and some faux black bolt heads and plates applied to get it to feel more rustic industrial / loft - afraid a fake ceiling is going to look cheap. The wood and black above will work with the off white walls. Consider instead of texturally painting the tv wall - let the "canvas" of all the walls stay uniform if you want this to feel large. The back wall is not the best for television anyway, if you want the room to feel large - the wall to the left of the door - (no window there, eh?) is the right place for a large flat screen wall mounted sort of center in the room (that appears to be the non-operable side of the double entry, typically unused) . Do a narrow console table underneath with drawers and lower shelves for the cable box. That can also be your laydown space and the rest of the room starts to live larger. I would run a large sectional in the beam recess area with the short end coming back just to become a lounge under the window (hang a stained board on angle brackets as a custom sofa shelf on the wall in the recessed end to fill it and provide a place for drinks) - the "beam" will make seating feel sort of sheltered there. It will work together . .you have a good long run nearly 8' there. If you want the room to feel big, a long sofa with a turn so many can gather for conversation is the best approach. Split the power for the television into two (easy 1 hour of electrician), patch this wall and hang wall mounted black iron sconces above the sofa back at two locations designed for the length of your sofa. Use a round iron and wood table at the sectional and a pair of great, small scale modern chairs facing the window set on the opposite wall. Consider a large scale modern abstract over the back of the sofa, and a gallery of black and white graphic photos framed in natural wood with black mats around the television on the tv wall. To the left of the window, hang some black iron hooks on a wall mounted wood board. With the wood, white and black iron, select your accent color carefully - neutrals for the main pieces - maybe some saddle leather for the chair pair. Color only in art - play off the green and white outside