Use Beverly's layout above, then get a retractable mounting system for your TV that allows you to pull it out from the wall and angle it.

The (real, licensed) architect drew in the same layout we’ve seen in suburban model homes everywhere. He freely admitted that these layouts are not his strong suit and didn’t want to spend any time in it. I didn’t share the drawing because I don’t want to get hung up on tweaking the original idea. I thought starting with a blank slate would inspire more creativity. Also, I’d prefer to have a round dining table for better interaction when we’re all together. I’d also like to avoid placing the TV above the fireplace if there are better alternatives.

If you want a TV in that room the only place it can really go is to the right of the fireplace (maybe to the left if you find that works better for you). It is never recommended to put it over the fireplace unless there is nowhere else for it to go. You have more than enough space on the right for a nice console. Maybe in the future you can do something more dramatic with the fireplace as it looks small in that large wall (or maybe you are already and it's not finished yet). Put a tall piece of art over it (something that is less wide than the fireplace). Face your sofa toward the fireplace and TV. The dining table should have the long side parallel to the slider. I can't imagine it fitting the other direction. I don't think it's a bad thing to have your old furniture in there for a while. It will help you get an idea of the right size for new pieces. You may also get better advice if you post a graph paper drawing of the space so the commenters know exactly how much space you're working with. The perspective in pictures is sometimes misleading.

My husband and I have done what you suggested by drawing up some plans We have started with the smaller version. Thank you for your offer of help. I think we are both realizing that we can’t get everything we dream of in the space as originally planned. He does not want to put a tv in front of a window because of the wiring etc. can be seen on the outside. He has mentioned also that with this size of room, it may be difficult to sit back far enough to view a TV. In terms of dining, since we seldom have a crowd for a sit down meal, I suggested that we not put a permenant dining table in. We can rent a table as the need arises and rearrange the room. If I can move my china cabinet to this space, it will open room in my 12x12 dining room so I can get a larger table in that room. If we use swivel chairs in the addition, we can easily turn the chairs for viewing or conversations. The posted picture is the latest version of our possible furniture layout. Floor lamps would go on each side of the sofa. The door to the left of the sofa will be a door size window so no traffic will go in and out here. The coffee table will be a padded bench with a tray. This plan may still be too tight We would love to see your thoughts with the original size space or the larger version.