So here's how I'd organize your dining room. Since you are clearly so handy, build a banquette the length of the wall under the opening to your front hall, painted to match the lower wall, with a reclaimed lumber seat, built in storage underneath (drawers are much easier to live with than hatch tops, but either would do), and add a bright fat seat cushion in a stripe or bold graphic print of your green, black and white. That would allow you to have fewer chairs, eliminate the need for chair clearance along that side of the table, and soften and warm up the space without losing your clean, industrial look. I'd use the bay window as the place for the sideboard, and customize the shape to the angles to make the most of the storage. Alternatively, a conventional rectangle would let you put a couple of tall narrow plants in the window - more life and warmth added. Then you'd have the option, if you have friends in for drinks and/or buffet supper, to push the table against the blank wall, and use the banquette for more casual seating. I'd furnish that long wall with a great big rectangular mirror - Ikea has several good choices - to open it up visually, and double the spaciousness of the wall opening over the banquette. Your hanging fixture could be chosen and installed so that it could be swagged up and toward the long wall, if you moved the table, so it would be low enough when the table was in its usual spot, and high enough so nobody would walk into it during a party. Two big graphic prints or canvases on either side of the wall opening, perhaps also a pair of candle sconces, and you're furnished and flexible.

@hiccup4 What is your vision for the room? What is its purpose? Traffic pattern, future furniture layout? Is the actual room open to the other spaces? How light or dark is it? Any architectural features? Your space above is pretty and transitional in nature w/great light, is that the mood and colourway you want to carry through? Or maybe you want a departure? Your rug choice is informed by all these questions. Any one of which will set a tone for the overall room. Make a mood board. Put a lot of your detailed choices on it. And a budget for the room. Collect pictures of rooms you love (and hate) with big brown leather Chesterfields. Doing all that will actually prove helpful. Way more helpful than rugs I would choose without knowing. edit: @hiccup4 Sorry I got you confused with the OP! Are you asking if that blue sofa on your sketchbook is a saturated colour? It is,just one with a lot of grey in it. (on my monitor)

I think the piece the TV is on would feel more at home in the basement with the chunky coffee table. Your home looks to be more contemporary in style except for the stair railing and the big empty display/bookcase. Do you have the budget to remove the built-in? That would give you some wall space for furniture and art. What is the exterior style of your home? Can you pull off a contemporary interior design and not stray too far from the look of the house outside? I don't think the DR is large enough to add more furniture there. I suggest a great piece of art and a rug that is 36-42" larger than your table top on every side. Pull the same colors into the LR with big art on the wall opposite the FP and above a 3-seat sofa where the built-in is. You can do another rug in the LR that is similar in style and color to the DR rug. For example, here are two navy rugs that could work together. The top one picks up your wall color, and the bottom one picks up on the fireplace stone.

Cute place, i see the challenge, but I am really against a sectional in this space let alone for guest to have to sit next to each other it creates a weird dynamic. I hope you are not planning to put the tv over the fireplace that would also be a neck breaker. I see the couch on the side the two red chairs. the tv on the wall with the lockers and 2 chairs to the dining room side.