In regards to the fridge, you have an existing receptacle. You should be all set, but it is always advisable to bring it up to code. Especially in the kitchen or other wet/damp areas.
Most of the equipment grounding conductors purpose has already been covered here. It also keeps all metal surfaces at the same potential. In the case of surge protectors, they use the ground to shunt excess voltage. If you do not have a ground the excess voltage goes right into the equipment and the only thing the surge protector is good for is providing extra receptacles.