Actually there is one reason for asking this: suppose you have Sky HD, and you connect the hdmi to your amp (although I know you don't need to for the audio, the optical needs to be connected, but stay with me here!) and the amp to the TV.
Now, say my other half comes along, who's morbidly terrified of technology (she is, I'm not kidding) and is happy to switch the TV and the Sky box on, but doesn't want to touch the amp because she's afraid of breaking it. If the amp is left off, will it still pass the hdmi audio and video through to the TV? When I say the amp is off, I mean it's still plugged into the mains, we don't unplug everything when it's not being used. Or can you only watch Sky on the TV in this situation if the amp is switched on?
I'm just curious because we don't have Sky HD yet, or an hdmi-equipped amp, so I can't try it.
Or indeed an HD TV... but we will and she WILL be upset if the amp has to be on for her to watch Corrie. So will I for that matter, I don't want that rubbish polluting my nice new amp and speakers...