Make sure the rug is something you won't tire of too quickly. Personally, I'd go for a more soothing, rather than stimulating, rug that doesn't constantly vie for attention, since the FP/TV and built-ins are your true focal point. Style shelves with 1/3 books, 1/3 large decor items and 1/3 open space. Your sofas look black and gray to me. Since the rug will be dominant, use colors from it to select cushions and drapes. You'd gain more balance in the space with a pair of chairs in place of one of the sofas. I usually detest loveseats (only lovers want to sit that close to each other) but your small space may do better with a love and two small scale chairs. With them you can achieve better balance by floating the love to face the TV, adding a small coffee table and placing the two chairs facing each other over the table. If you get swivel chairs, they'll easily turn for a better view of TV.

Can't really tell what color your couches are (one is blue and other is brown?). I would then incorporate your rooms colors and since your samples are so different, it's hard to recommend a style. I like the look of the style below which feels modern and casual. Linen drapery in dark beige hung on a thick wooden rod would be nice. Look at pictures of bookcases on Houzz to help with decorating shelves. Add some pillows that have buttons for that casual look. Wondering if you will be adding a coffee table and have you tried your two seater facing the fireplace and then place a floor lamp between both couches.

if you're going to keep the rug (which I like), you can put glass and ceramic pieces of the colors from your rug on the shelves. Black and White photo wall above sofa and more photos (preferably family) mixed in on the shelves.

The sofas are very heavy so I think a light scaled rectangular coffee and end tables would be nice. Adding metal and stone/glass/marble for the top would also help the room. Glass top would allow the rug design to be seen. Look for softer edges to match the geometric pattern in the rug.

I really like the rug in the first picture. There are some great colors you could pull out of there for accessories. Greens, gold and brown. The pillows currently in the room work with it, though I would probably have fewer patterned pillows. One or maybe two patterned pillows is plenty, then add some solid color pillows to tone down the patterns. The rug is quite a lot of pattern in itself. What I notice is that everything in the room right now is all angular - so many right angles. For balance You might add some rounded shapes - oval or round end tables or lamps, some rounded vases or bowls on the shelves, (hammered copper would look great) or a globe if you could find a smaller one that would fit on the shelves.

Thank you everyone! I am also trying to fill some colors in the room as I feel the room currently is all maple and black. My couch is dark grey in color which i recently bought. Thanks to the advice I got on houzz only :). I did not go for 2 chairs as I have a small kid and i thought easier with a love-seat instead of him jumping from one chair to the other and hurting himself.

I agree with decoenthusiaste that choose the rug that you don't tire of soon, but to add the colors that's the only way. Didn't find any rug that is subtle enough but at the same time adding colors to the room.

Thank You you Carrie. Very true, there is nothing in the room which is oval or round. All angled furniture. I have bought a side table blue in color which i really like, not in the picture. I was thinking to give the room blue and orange color combination. And that's the reason for the rug selection. I bought solid orange color 2 pillows and other one blue and orange pattern on cream base,

Is there any way, I can add the rug I like in a pic and see how will it look?

Love the colors that are in the rug options you posted. I love the blue one with the scroll tile pattern. Here is another rug that will look great in this room. The neutral color in it will go so well with your built-ins. Since the area is a bit on the small side I would also think about adding some drapes to the windows. It will heighten the room and make it look larger. For your shelves here is a great blog post about how to style your shelves.