When designing a home, create a communal core than can become the center of the family's life together, with more private spaces around the edge of the communal core for individual family members or subgroups. This allows people to engage in indvidual activities while remaining connected to one another.
A window seat such as pictured here is a great way to create an enclosed, personal space at the edge of a larger common space. Not only does this allow one to occupy a personal space while remaining connected to the goings-on in the room, but it can also create a place of refuge and outlook where one can remain connected to the outside world at the same time.