What is the depth of the couch? The length, width and height of the side tables? Ditto for the arm chair, the size and shape of the ottoman, the height and width of the entertainment center. Is there a desk chair? What is the width of the desk? Does it have an opening in the middle or on the right or left side? Is the back of the desk finished? Right now, making guesses, I can't fit everything into the space unless you don't want to get into the dining room, kitchen or hallway :-( It's not the lack of wall space; it's the lack of space for all your furniture.

You might consider moving the sofa to be centered in front of the window and put the chair nearer the door adding a pony wall height bookshelf (with its back to the chair), with or without doors on the entry side, between the chair and the door to create an entry; perhaps something like this: http://thegamersforce.com/ikea-glass-door-bookcase/bookshelf-inspiring-low-bookcase-with-doors-bookcase-with-doors-ikea-dark-brown-bookcase-with-glass-glass-door-ikea-bookcase-singapore-ikea-glass-door-bookcase-ikea-billy-bookcase-glass-door-instruc/ A barrister style bookcase could also work. Such a room divider would give you a place to add a lamp to the room.

I wouldn't do that fireplace surround. It's jus not a good look w/the type room/decor you have. try it elsewhere. try craigslist and similar sources for rugs, tables, shelving. as for the room layout, for the wall that's next to the doorway, and to the right of window (pic #3 up top) what if you did some cool shelving or book cases? I'd also look into doing some sort of shade or blind instead of those bulky drapes. This is a simple layout you could copy. a larger sofa w/a chaise would work for that room better than your two sofas. if doing a tv, try a shallow console and mount the tv to the wall. you can do a 'coffee table' by utilizing an ottoman or something similar. this type of sofa against the large windows would work out better. notice the blinds, nice contrasting paint color on the walls, colorful rug, potted plants. same layout. Imagine your windows are behind the sofa. shallow shorter shelving on the opposing wall is great for kids toys and books. mount tv. fabric ottoman for coffee table. neutral rug.

As far as arranging furniture with the columns, I would tend to ignore them and group seating around the fireplace. You are always in good company with a more flexible 3-seat sofa and two upholstered armchairs (or swivels.) I think a sectional will just add another complication to the space. What is opposite the fireplace? Are there any floor outlets near the columns or actually in them? Is there any electrical wiring in the bulkhead above them? They might be interesting if lighted. You could also install some glass shelves between the two that are near the exterior wall. Lighted from the top, that would be a great display for something like colored blown glass. As for the lighting, you can find less expensive variations on those. Scaling them for your room size will also lower the price somewhat.