I've heard it said that Wii games are more kid/family friendly than the other systems but we only have Wii so I really can't make a statement from personal experience comparing various systems.
That being said, even though we have the Wii, the kids don't use it nearly as often as their PCs. If you are looking to play games as a group then the Wii is a better choice than a PC, but for individual games I think it's a lot cheaper to just download games for a PC. DD also has a DS which is good for taking on car trips or other places where she needs something to occupy herself. The DS is a handheld, portable system.
In terms of educational options there are some game choices but they can be hard to find. DD likes Professor Layton games like this one for the Nintendo DS, for example. They are basically puzzle games so involve some mental stimulation.
http://www.amazon.com/Professor-Lay...9685819&sr=1-4&keywords=professor+laytonDS spends a lot of time playing historical games on the PC (games similar to Civilization) and has learned a lot about geography/history. They are both also into Minecraft on the PC which involves some thinking and creativity.
