You haven't said what size the table is. Your rug should be 4 feet wider and longer than the table yet not run into the wall furniture. That might help you determine things. If you can empty the room and use blue painter's tape on the floor you can "vision" how it will all fit in.

I agree with putting the sideboard on the larger wall. This way you create a focal point and blabance out the table.This also gives you the oportunity to put a great piece of artwork above it.

Wait until the table is in and have a dinner after that. See if guests have plenty of room to pull out chairs.

My own dining room (just measured is only ten and a half feet wide), I have placed corner cabinets in three corners and a small round table in the other. On the long wall I have a one foot deep bookshelf. But then, my table is pretty narrow.

The table is 42x72. I took out a sideboard that I just didn't like. There is room for it, just wondering if it would look better somewhere else. Now is the time to decide before I buy a new one! I've been remodeling for most of the year and have found myself agonizing over every detail.

Oh and the rug is 9x11. I am getting a new one as this doesn't look nice with the colors in the adjoining room. It will be the same size though.

If there is room for it, I would go for it! Have you sought help for the furniture store where you purchased the table? They often have very good folks to help.

I did but got some bad info once and wasted $2000 so a bit reluctant now. By the way- I love the corner cabinets in the photo you posted. Very pretty!

I would wait until you get the table, chairs and rug in the room. It seems you are going a little more contemporary so you might not want to fill the room up

Do you have a leaf in it now? If you will not be using the table on a daily basis, you can remove the leaf and it's possible the sideboard will fit. I have this same issue. I just removed the leaf and put the two additional chairs in the opposite corners of the room out of the way.

Would love to wait but have been working on this for a while and having an event here in January. Hubby's got me under pressure so need to make decision!
If I were to do the sideboard on the long wall and maybe put a corner wine cabinet on the wall opposite the window, would that look too crowded?

I would start with the sideboard and enjoy the event so you can see how the traffic flows in the room. I think finishing the room with draperies and accessories will help create a cozy feel.
I don't see a photo of the the wall opposite the window to be able to tell you if it would be too crowded. Sometimes less is more.

I am assuming the 42 inch width would be parallel to the 12 feet wall and 72 inch length would be parallel to the 13 feet wall. Calculations show that the appropriate place for the sideboard is between the longer side of the table and the longer 13 feet wall as there would be a 51 inch space between the table and the wall. You need about 3 feet distance between table and sideboard for a comfortable clearance for chairs and walkway. That leaves 15 inch depth for a sideboard but I think you can go up to max 19 inch depth.

Distance between the shorter side of table and the 12 feet wall is about 42 inch which is too narrow for a side board. Besides, you only have 1 feet of clear floor space between rug and wall.

If the sideboard goes on the long wall a mirror can't be aligned to reflect the chandy. I'd want to lower the chandy just a tad and put the sideboard and mirror opposite the window to reflect the chandy and the view. If it weren't for the wainscot, I'd suggest a floating sideboard like this. I don't find any pix using one with the wainscot. Would you be interested in removing it to enhance the more contemporary feeling you're going for?

Don't let hubby put you under pressure to make a decision. Sometimes they just want things done too quickly! Furniture is expensive and you will be living with it a long, long time!

And for your January event, I imagine that space to circulate around the table may be more important than whether you have a sideboard! I would get some 96 inch long drapes up (two sets on each side for a full rich look) to cozy up room.

To fill the wall for the event, maybe steal art from another room?

Also think about lighting for a night time event (see Deco's photo). Maybe a couple of uplights sitting on floor with a plant in front to cast great shadows.