RS485 Lightning Security Surge Arrester Protection Device YJS2103- 485C

Any well-known major brand (Belkin is just one example) and it should be plugged into a grounded outlet without an adaptor.
If your home has circuit breakers instead of fuses, this is preferable too.
Finally, I'd recommend a surge suppressor with a phone jack unless you're 100% wireless (a surge can also fry your PC through a phone line).

HD has nothing to do with it. The danger is always there with lightning, especially with a rooftop antenna or satellite dish. The best defense is to completely disconnect your antenna and pull the power cord (your surge protector protects mainly from minor voltage surges on your electrical service, not a lightning strike).
The hazard is a little less with cable TV distribution that is buried rather than pole-mounted, but the hazard is still there.

The surge protector does not need to "stop a lightning bolt". All it needs to do is clamp down on the residual voltage created by a nearby lightning strike which can be a pretty high voltage.
If a lightning bolt went through your window and struck your TV (not likely) the surge protector would obviously be useless.
They do work it many circumstances but not every conceivable one. Every valuable piece of equipment in your home should be on a good surge protector. Don't forget to protect your incoming cable and phone lines too. Lightning is very sneaky.