Mike Slater I can see why you want to make improvements. A few questions: (1) do you own or rent? (2) What is your budget? (3) Can you identify a style you like: contemporary, modern, country, etc? (4) Are there any windows at all? (5) What are the dimensions roughly of the room?
One of the biggest challenges is your big u-shaped sectional. Are you willing to change it?
Alix Flamm What would probably work better is an entertainment bookcase furniture piece. The TV is the focal point in the room right now. You could also add some shelves above the TV add books and vases and other interesting items. Maybe add some plants too.
pruner Thats a huge TV - is there another aspect to this room (eg window) that could become the focal point, if so a rearrangement would help. If not , move the lounge away from the wall, add some colour and soft and interesting texture through art, 'touchy-feely' cushions, lamps and rug ...
One of the biggest challenges is your big u-shaped sectional. Are you willing to change it?