Hmm, I never thought about that - I love being in the kitchen by myself, I usually close the door to the family room, but I can see that at other times it would be nice to not be alone. Big sliding doors might be a good compromise.
Incidentally, that compromise is one of the reasons why triple-deckers in the Northeast often have double doors between the large rooms in the house. (It's really nice when they're pocket doors, too, and they just slide into the wall.)
