I wouldn't do anything black. With the pale, neutral background and the very-saturated red of the sofas, I think it could end up a bit 90s batchelor pad. Instead, I'd tone it down with mid-toned wood, anywhere from oak to teak, and some soft, contrasting accent colours: maybe hessian-coloured cushion covers. You could have a big, tall plant in the corner by the French windows.
And definitely pictures, but don't rush those. Better to have the walls a bit too bare than to buy any old picture just to fill the space. Get things you really love, whether they're your nan's old oil paintings, a child's drawing or an ikea poster framed, or quirky vintage plates from the charity shop. It doesn't have to be something enormous, set square in the middle of a wall. In fact, preferably not. Small items can be clustered together, and should take a step back and space pictures out relative to the furniture, windows and doors, and the fireplace. You definitely don't want to concentrate all features of interest into one place.
What furniture? Well, I'd have a big bookcase, and maybe a side table with a lamp on it, against the wall opposite the fireplace, and I'd have the chair over there as a place to sit and read. I'd change the tv stand for a wooden corner unit. I'd bring the sofas forward off the walls a bit, facing each other across the fireplace. It's a lovely big room, so you can afford to cosy it up a bit, and it would help take some of the focus off the telly. I've never really done coffee tables, partly because I've never had the luxury of space, but I also find side tables more practical and versatile. A nest of tables, scattered at strategic points around the room means you can have your cup of tea at your elbow, while somebody finishes their homework over the other side of the room.