It seems like a big enough space that it will always have two functional zones. However, I think you could widen the seating area around the TV, and then put something else at the fireplace end, like a couple of arm chairs with a table between them (for rading or watching the fire), or a game table with a storage cabinet.
For the main grouping, I think I'd put a couch facing the TV (or at least the wall with the fireplace on it), and then a chair in front of the window and one or two more facing the window. You'll want a much bigger rug, and a couple of end tables with a lamp or two. You can push the couch a little farther away from the walkway to the bathroom (?) if it's not part of a sectional - the chairs work better for conversation too, and allow a variety of TV viewing angles.
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Size of room
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