1. Drawing rooms. Drawing rooms, a shortened version of "withdrawing" rooms, have been around for a long time. Originally they were located outside royal bedrooms—a spot for the court to spend time—though by the 19th century, they were in the main part of the house, off the parlor, and provided space for the men's post-dinner cigars and brandy (the little ladies stayed in the parlor).
Lifestyle changes (lack of servants, again) and the sexual revolution made drawing rooms obsolete, but I think the concept, at its core, is a good one. After dinner, it's nice to have a comfortable (and pretty) room to sit in with friends. I love post-dinner chats and think it's nice if they're in a place that doesn't involve dirty dishes or a stained tablecloth.