A more casual space just relaxing, and family time! With an open concept space its usually open to kitchen and eating areas, plus it's always in use.
For watching TV, visibility is the key. Everyone must have a good seat. And the "man of the house" needs his recliner with perfect line of sight, and immediate access to the remote.
Create a space for reading with a cozy space to sit or curl up, and adequate lighting.
The decor for the family room should reflect your lifestyle, activities, and how many people you would like to seat.