Can you post some pictures?

Its tough with narrow rooms. I would have set the TV where the wooden shelves are next to the doorway. That way you can place the couch further back and not break your neck looking up at the TV. Dark flooring was interesting since the room already looks very dark.

In in an open plan space (as opposed to a separate formal lounge) I would skip on the fire place. Perhaps put in place what is required to install one down the track but I feel life will be simpler and the space more useable for a young and growing family without it. Similarly, easy access for kids to come and go from back yard is handy. A tv on the wall is a good idea for safety (avoid toppling it) and for protecting the screen from sticky hands. We had a near miss with the fairly sharp corner of our tv unit and our son's eye when he was a toddler!

Lisa, you could have flat front cupboard doors or drawers at bottom of unit, and either full width shelves w/o middle divider (for TV etc) and some with middle divider for ornaments. I wouldn't off-set or stagger the shelves so you have a uniform look on both sides (with exception of where TV will sit). Having said that, you could also have shelves mirror each other exactly, then if you ever want to change position of TV (or the person who might live there in future), it is easily done. I would go for a simple design without embellishment except perhaps in the door hardware.