As far as I know, the ground provides protection from high voltages and provides protection to the equipment. If you have a direct lightning strike your out of luck regardless.
Equipment ground will work without a grounding rod, like oldhvymec wrote the grounding rod is for over current from outside your home. Audiophiles that use isolated grounding rods are actually putting themselves in danger because if there is a fault in a circuit some of the over current could go to the isolated grounding rod and then the breaker won't see an overcurrent and won't trip.
