How to Do It Right Instead of lumping public rooms into one vast open space, a better option is to properly arrange a group of normal size rooms (with normal-size ceilings).
With the cunning use of french and sliding doors, rooms can be closed off when needed - say, when one person is watching TV and another is doing the family's taxes - and opened up when you want a more spacious feel. In the end you wind up with as much square footage as in a great room but with a more intimate, livable feel.
Typical great-room construction: $150 to $350 a square foot
Building a collection of normal rooms: $125 to $250 a square foot.
Bigger is better? No, bigger is more expensive.