The nForce2 will play games, but not super well. I've had success playing BF1942, SOF2, Rainbow Six 3, and Call of Duty on a nForce2 board with onboard graphics, but the resolution was turned down quite a bit, and almost all extra graphics features were turned off or low. If you were to use the board I suggested you won't want to play any 3D games, that's for sure.
The board should fit a full size case. I don't know why it wouldn't.