Thank you for your replies. kew 2006: I moved the living room furniture in front of the wall unit in several different configurations. Unfortunately, it just looks awful. It is way too crowded and impractical with furniture blocking the wall unit. So I guess the issue is function vs. aesthetics. If I get the DR set, the wall unit has got to go. But since I need the storage space, I would probably buy a wall of Ikea bookcases and put them in a bedroom. Is the new DR worth the trouble?

I have a DR that is almost 13' square so mine is close to your size. My DR table (without leaves) is almost exactly 56" square. It looks great when no one is eating at it, but even without putting in a leaf (it will seat 5 a bit crowded, 4 better), it is hard to get around. I have a small sideboard on one wall, a chest on another wall, and no furniture on the 3rd/4th walls and it's still crowded. Serving is a nightmare as I cannot get behind the chairs to go around the table. If I put in a leaf (my leaves are about 24" wide), I can seat 6 comfortably. One Christmas, I had to put in 2 leaves, and the people at the end, well, one had his chair practically in the entrance into the LR, and the other was up against the french doors that lead to outside - it was awful and this was to seat 9 people! I cannot imagine how you can possibly use your table in this room, or any other table and hope to seat 10 people. It's just not big enough. It takes a BIG DR to hold a table that can seat 10 comfortably. My DD has a DR that is 15' x 16 1/2'. Her table is 52" wide and if she uses small chairs, she can seat two at each end and with two leaves in her table (a triple pedestal table), she can seat 4 down each side, thus 12 in total. One time, she seated 14 - it was very cramped - no b&b plates, single wine glass in the table setting.

@GN Builders L.L.C That's what I was thinking, but would it be too close to the corner of the couch (if the couch was between the closets?) Unless I rotate the couch to face the short wall instead of the long one, but that might be too tight as well...

The logical place to put it would be under the chandelier (after upgrading it severely.) There are charts all over the internet to help determine size and shape for a specific number of people. Google for those and then decide on shape. Tape it on the floor under the chandy with painter's tape to see which one works best in your space. Don't forget you need 38-42" of clearance all around the table for chair scoot and sit space. If you plan for a rug, it should be 38-42" larger than the table yet not run into other furniture. If you entertain larger groups only once or twice a year, you may prefer a drop leaf or extension style table for those occasions.