Post a few more photos (one showing the wall the fireplace is on.. this room has tons of options !! :

Some suggestions:
* Lose the blinds, put a thick oil rubbed bronze curtain rod up with cream panels hung as high as possible.
* Lose the fan. Lighting is the most overlooked aspect of decorating (according to Candice and her spaces are the best. Add a dramatic light, look at Restoration Hardware for ideas, then buy online. A chandelier would be cool, too.
* Add a large brown sofa and an old trunk for a cocktail table. I wouldn't put it against the wall. I would float it in the middle of the room and position it parallel to the fireplace, facing the fireplace.
* Flank the fireplace with 2 chairs in cream linen, facing the sofa.
* Add a thin wall unit to add height to the wall behind the sofa. Since the sofa is floating in the middle of the floor, the wall unit will fit nicely on that wall.
* Behind the sofa, I'd add a thin sofa table, if there's electrical, add lamps on either end of the sofa table. That way, you have light at the couch. I would definitely buy deliberately ;

I think your best option for seating is an L sectional positioned on the wall with the long arm of L coming down along the window wall. It looks like your fireplace wall is wired for the TV so I'm guessing you'll put it there, but I wish you wouldn't. Not sure you have room next to the fireplace for the TV. If so, I would paint the fireplace niche white so it stands out vs. the same color as the surround. You can add some decor in there with lighting. If you Google Image Fireplace Niche decorating ideas hundreds of pictures come up with ideas of what to display there. Also, if it were me, I would pull up that rug. I see a border of hardwood floor in the picture and if there's hardwood under that rug, you should display it and get an area rug instead.

Do you have more photo's of the room?