We have four chairs around the table but it can extend to six chairs (we do have two extra). We also have 4 bar stools which are more frequently used than the dining area. I do like the idea of having a large formal dining room and lots of guests to entertain, but it hasn't happened yet.
At the moment six but we have a much bigger dining table in storage that seats eight in normal form but extends for ten or even twelve I think. When we moved to Belgium, our house there had a very small dining area, so the table and matching chairs went into storage. We left it there when we moved here (Germany) but now we are about to move back to England and our lovely big table and chairs can join us again there :)