turning my system on during lightning storms

All the above is great advice. Also, the satellite dishes can carry spikes and lightning into your receiver, as can FM antennae. I am having an electrician install ground wires and rods for my dishes and antennae, and I unplug the things I don't want destroyed. Even small static discharges can harm delicate electronics.

It is true that the grounding rod only prevents the static discharge issue. Also, it probably protects you from your insurance company if they claim that your negligence of putting up an antenna caused lightning to strike your house. A direct hit will take everything out. A neighbor had his house burn down when the lightning strike fused the circuit breaker box and the wiring fried through the walls and the house was fully involved. lesson? unplug everything, and insure it!