I blogged about this once in more detail (like you care), but I think workplaces would benefit greatly if they had zones that were analogous to those found in houses.

  House                   Office
  Bedroom/office/study    Private Office
  Dining Room             Small team collaboration spaces
  Living Room             Common lounge
  Backyard/family room    Whole company meeting room/auditorium

People stay in their bedroom/study when they want privacy and the ability to concentrate. They hang out in living rooms and dining rooms when they want to see other people. When you have all your friends over, you most likely spend your time in the kitchen/family room/backyard. I don't see why your workplace should only have semi-private personal zones (bedrooms) or a single huge room (family room). No family would like a house with only bedrooms or only a family room, so why should employees like a workplace with only one type of room?