There is no right or wrong. Generally do what works for the room the best. Keep it simple. A good center piece on the table is often more appealing than a set table.

The one big negative I find with the table being set for a meal is I notice more that the place is being staged when what I should be noticing is the house itself.

You'll get both sides of this question. Some buyers laugh at staging the dining room table and think of it as being blatantly phony. Others think it looks inviting to set the dining room table and sets the tone for the room. The majority of the times when I sold, my dining room table held only a centerpiece and a table runner. The last time I sold, I set the table with china and napkins and a centerpiece. It looked nice, but I don't think that setting the table sold the house, it just made me feel like I was taking all the steps to do the right things. If you do decide to set the table, don't overdo it. You don't want buyers to focus on the table and it's setting, you want them to focus on the room and imagine themselves in the room.

I prefer a table runner and nice centerpiece, and feel that a completely set table looks like the seller is trying to hard - or that I am interrupting their dinner time!

I totally set my table.
The dining room was small, so I had purchased a smaller table and chairs to help the room look larger. Without setting that smaller table it looked almost like a child sized set. So I dug out some small plates and bowls, placemats, a nice tablecloth and managed to disguise the tiny table a bit. I definitely think it helped.

I did hear not to set out any flatware as it is easily stolen so I didn't do that. I don't believe I did glasses either. Just tablecloth, placemats, a small plate, a small bowl on top of that and a nice centerpiece.

Just enough to tell them "You eat here!"

That was the whole theme of my staging- each closet had two items on a hanger and one pair of shoes on the top shelf to say "You keep clothes here!". Linen closet had maybe two towels and two washcloths stacked to say "Linens here!" Kitchen cabinets had extremely sparse contents- "Dishes here!" and "Food here!" Same with the garage and everything else- it looked like I had scads of room for everything. Which I did not- I had a POD full in storage and a friends garage full of more stuff.

But it sold :)