We have it set up as best as we can for teens - we bought/modified the property with them in mind.
On the ground floor we have a big kitchen/dining room for family tea. We also have a living room which is generally used by DH and I unless there is an occasion which causes us to come together (eg Christmas). I have an office on the ground floor too, and there is a little loo and a utility room. We're contemplating a conservatory as a dining room in the future.
The basement is predominantly for the kids. The main area is open plan - We have a big TV down there and sofas, a pool table, a 'bar' area (not stocked with alcohol, but has fridge, drinks, sink, glasses etc.) There's also a loo down there so if they have friends round we don't have to see them! There's a second room which we turned into a dance studio - it has a wooden floor, iPod docks, cupboards with their costumes and shoes in, mirrors on one wall and a short barre. They have spent hours down there as kids and teens, so it's been worth the expense. It also has a TV so I can do my exercise DVDs and a treadmill.
On the first floor is our room (with en suite), DD3s room, DD4s room and their bathroom. On the second floor is DD1s room and DD2s room, plus bathroom. The large landing space has 2 big tables for homework, laptops etc plus storage shelves for all their school books.
Oh and DH has a shed in the garden!
We're very lucky to have so much space, but a lot of it is careful planning. We bought it as a 5 bed house with 2 bathrooms plus downstairs loo and en suite. My office is what was advertised as a dining room. The basement was just garage/cellars until we renovated, but we wanted somewhere the girls could see as their own entertainment space for friends, but that we were on site if needed.