B.S.
I think the Wii is a perfect gaming system for a family. The games tend to come for more than one player and their are so many different games out there. Any other game system I believe is geared towards one player. My husband has a PS3 and their are only a few games out there that can be used with more than one player or in a cooperative manor.
If you go with the Wii and have 4 kids you'll need to buy for starters 3 extra controllers (Each 35-50.00 a piece). It comes with 1 controller. Then there are more accessories you can get from that point on, nunchucks, Racing wheels...etc. But the controllers are first priority.