Another vote for Belfort. We bought this set and added the bench:
http://www.belfortfurniture.com/item.aspx?itemid=1024970527&itemnum=KG-TA-4290B-RAI-C%2b4xCH-735C-RAI
The table legs are traditional - the chairs are more contemporary. We had the same wish list - transitional style, seats 6+, affordable. Chairs are very heavy/sturdy. Chair pads are faux leather, but they look nice and clean really easily.
It seats 6-8 as is - if you open the butterfly leaf (i.e., it is stored in the table itself, folded underneath), it seats 8-10. We ordered a piece of glass for the top to protect the finish since we have young kids.
Got the whole set (table, six chairs, bench, with delivery) for $1500. Not heirloom furniture, but nicer quality than some of the Pottery Barn furniture we've bought over the years. Had it for more than a month and so far, so good.