Here's a more accurate room layout with the dimensions of the room and recessed area for the TV. The very simple website I was using doesn't really let me specify an open archway or change the layout of the walls to reflect the recessed area in the corner with the door, but I don't think it matters much. I'm more concerned with having seating for at least 5 people, not obstructing the window view, and giving everyone a good view of the TV. I was thinking perhaps the chair on the left should be a swivel chair, to allow someone to turn and watch the TV better. I could do without the chair there at all, but would like to have family over on occasion and it would be nice to seat more than 4. Do you guys think this would work?

You do not give any measurements, and that makes it impossible to envision. Measure each wall in the room. Measure from a corner to door and window frames. Measure the width of the door and window openings. Draw out the measurements on paper so that one foot equals one inch. You don't have to use graph paper, but use a ruler to keep the scale accurate. Position the door and window openings as accurately as possible, and if a door opens into the room use a curved arrow to show which way it swings. When everything is drawn out look for obvious pathways. Since you describe this as spacious, there should be room to walk around furniture groupings. Next measure your furniture—sofa, chairs, tables, bookcases, TV, etc.—that you plan to use in this room. On a separate piece of paper draw the outlines of these pieces at the same one foot equals one inch scale. Label each furniture piece and cut it out. Now you can lay these furniture pieces on top of the room floor plan and move them around till you like what you see. Here is a picture of one room plan. As to where to put your TV, many people put it next to the fireplace so as to keep the focal point on that wall. If there is not enough room there choose another wall. Don't place the TV in front of a window, especially if you watch TV during the day, because the backlighting causes eye strain. All the guides I have recently read say the bottom 1/3 of the screen should be at eye level of a seated person. These guides also recommend sitting much closer than I would have thought, and that distance varies with the resolution of your set. For instance, a 40" 1080P HDTV is best viewed between 5' and 8.3' away, whereas a 40" 4K Ultra HD TV has optimum viewing between 3.3' and 5' away. Here is the link to that info. That seems ridiculously close to me. Should you have no suitable wall for the TV consider using furniture as a room divider to hold the TV as below.

A living room. Right now we are using it as a empty play room but would like a living room. This room is open to a family room where we have a tv over fireplace and sectional. I am replacing the sconces with more modern ones. Also, the furniture that is currently in this room would go down to the basement. I envision reading in the room, entertaining/sitting, and also having the kids play?

Do you ever use the FP? Is it real or gas/electric? Is the closet built in or free standing? Looks like it might do well in a mudroom/hall. What is inside the bulkhead over the windows? Why don't you move the mirror to the dining room and get a nice chandelier to be doubled by it? Your dining rug is too small. Needs to be 6' bigger than the table so the chairs don't fall off it when in use. BUT it shouldn't run into baseboards or furniture on the walls. Maybe do without it and soften with drapes instead. Can you take a pic standing in front of the TV?