If it were my space, I would do something like this:

The sofa I used in this rendering is 100", but I would definitely consider keeping it right around 100-105"--something without a chaise will make the space seem larger and less crowded.

Hope this helps!

I would actually put the TV in rthe samller sapace with a shorter sofa facing it and the have the fireplace area as a conversation use.

@Denise, I think if you're going to get 2 lamps on either side of the sofa, 100" will definitely be too large. Estimating the widest part of a floor lamp shade is 18", you could do 1 lamp and get away with a 80-84" sofa, or 2 lamps with a 62-68" sofa.