To visually open up the room I would suggest lighter drapes close to the wall color without a pattern or with a self pattern. I would remove the stair ladder deal in the corner (they were a passing trend) and clear the TV chest of everything. Consider doing a grouping of pictures around the TV and above it to fill in that area and give the room some needed visual interest. Beverly's layout is very nice, although I've personally found that darker drapes tend to close in a room, but it's your preference. I would consider a rug an absolute must.

No space here for a sectional. You might consider a reversible chaise sofa to get the look and to be able to switch the chaise portion from side to side for different arrangements. Really, a 3-seat sofa and two arm chairs would be a better choice.

yes, now if this is not really possible, we will find a solution (in the bedroom or office ...) TV idea :

Ignore tv unit, matching one arriving this month