Before adding art to the walls you might want to finish getting your furniture. It seems that you especially need tables/lamps. Overhead fixtures are the worst for creating harshness and making everything and everyone look bad. Are you adding chairs? Have you considered a more colorful rug? Once these things have been determined it is time to think of art, You should not just go out and buy stuff for the walls, Take it slowly and wait till you see things that you love or have meaning. The decor can be things other than " pictures". It can be plates, baskets, funky objects, wreaths, etc.

I just moved into our house we built and I need help with the arrangement of our furniture. Also ideas for living room decor.

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.

Are you okay to put the TV above your fireplace? If concerned about having all the wires dangling down, you can have an electronic "eye" installed at the bottom corner of the TV that to operate your TV components using your existing remotes...i.e., cable box, speaker/sound system, DVD player, etc. They're fairly reasonable and easy to install. Then move your TV cabinet next to the fireplace and add some decorative items (vases, candles, books) on top where the TV currently lives. All the wires would get fed through the wall and into the back of the small cabinet to the components. My husband installed the "eye" on our TV that is above the fireplace. All the wires are fed through the wall to the built-in next to the fireplace. They are completely hidden away. A clean look, no wires hanging down, components hidden away. Next, by moving the TV above the fireplace will free up the space in front of the window. Maybe relocate the loveseat (for now until you get something else) in front of the windows. This will improve traffic flow and help both spaces more open. We have a similar situation between our kitchen and family room area. I've found that keeping that area open makes feels and the foot traffic flow better. We have 2 dogs, 2 adults, 2 kids...lots of feet :)