We built a big house last year and by far the best bit of it is....THE PLAY ROOM!!! It saves my sanity big time.
We have a tv, dvd player, book shelf, a big train table, a comfy breasftfeeding couch, bean bags and tubs of toys in there. And although, we still get some toys through the house it's so manageable! If I'm feeling lazy, it doesn't get cleaned and I can just shut the door! We have french style doors on it too, so we can see in there from our living area.

Toy rooms are a neccessity!