Naturally he takes over the whole house when he plays but I've tried to create a few designated storage areas for his things. In the kitchen he has his own cupboard which has kitchen related play in it.
As well as a pretty standard set of play food I put empty packets and tubs in there, as they get used, so each day he has a new item to use. It's nothing spectacular and he usually loses interest in it after a morning of play but it keeps the kitchen role play going nicely without the need to buy more and more foody toys.
One important and yet sometimes costly lesson to learn when having children is they usually favour very simple things over expensive toys. Apart from a ball, some toy cars and his ride along Joel likes nothing better than to climb and run round the house with seemingly important things in each hand, being busy playing at being busy, and I like nothing better than to watch him, when I'm not playing at being busy too that is.