geokid, that is actually what I think my husband and I will be doing! What a coincidence! Over the weekend, we tried almost all the layouts suggested (much to my husband and everyone who had to help's horror), even went back and forth a few times, and have settled on two arrangements that will work best for us. In either arrangement, the sofa is going to face the fireplace. We'll have two slimmer side chairs with a opposite from the sofa. We most likely will have the TV mounted on the long wall with a smaller cabinet or mounted cubbies/shelves (something) for the electronics. I might add in a small tufted bench opposite the TV if we need more seating, but the two side chairs should work for now, and when my family/friends come over to play video games (which seems to be really often lately), we'll pull the chairs over. But realistically, we all sit on the floor. The piano will stay along the stairs, and to balance the open wall space between the piano and the sofa, we'll mount some shelves for decor and books. We tried mounting the TV over the fireplace, and I surprisingly liked it, too! It totally cleared up the floor space and made everything so open, but...it was kind of uncomfortable to look up at the TV. I'm only 5'3"; I don't mind a few minutes like that, but not for a couple of hours and not for game-playing. It's fine for my husband, though. I'm still keeping this an option, as I think we won't really know what'll work for us until we start buying some new furniture. I tried placing the piano in the dining room; no good because it ate up too much room. The bookcases are currently there, and I kind of like it! LOL. We have no dining table yet, so it feels like a special reading room. Haha! I like the idea of the bench along the window. If our chandelier was centered in the room, would it look weird for the table to be off-center? Otherwise, my plan was to buy a narrow table, have bench seating on one side (probably closer to the bar area) and regular chairs the other side.

One suggestion...figure out your floor plan before you put down the new floor so that you can add at least one electrical outlet in the middle of the room where it will be hidden under the sofa. I think you will end up floating furniture to make best use of the space, so it would be terrific to have an outlet to use for lamps to avoid cords across a pathway.

Offset fireplaces aren't really planned to be main focal points or centers of furniture arrangement for all of the furniture in the room. Particularly if you are going to use midcentury furniture, you can ignore the fireplace to some extent. Not completely but you don't have to center the room on it.

I think I would also move the TV to the 9'3" wall as Barnes Custom Builders suggested. I would then move your couch to the 5'11" wall (pulling it away from the wall so the vent can function). Then, I would flank the chunky chair to the left side of the couch. I would purchase a TV credenza and mount TV above. I would then fill the previous TV location with a credenza with a lamp and a mirror. I would also get a single large piece of artwork for the 11'9" wall. I would get rid of the bent wood chair as you suggested. Here's an option for a rug, credenza, media console, lamp and mirror... Moroccan Tribal Cross Section Rug Geome Sideboard Seno Media Cabinet Ripple Ceramic Table Lamp Wall Mirror Brass Hope this helps or inspires!