I've lived with my lovely new Samsung 32" screen with HD for a few days now and it shows up that TV standards are very much a myth. My viewing is on Telewest cable in the UK, but I suspect that using Sky's HD service would have the same effect.
The major problem seems to be that content delivered via satellite gets compressed to hell and makes a mockery of 'standards' such as HD, which in its current implementation, is very variable.
Frankly, the World Cup in standard definition (SD) looks dreadful. In high definition (HD) it's better, but still grainy and over-sharp in wide shots. It's an irony that the very content being used to drive HD in the UK does little to flatter the medium. Drama and documentaries look brilliant, but the overfussy graphics and virtual sets of the newsroom are less overwhelming.
The same is true of delivery using broadband TV formats such as Windows Media, where there is nothing tougher to encode than a wide shot of a football or field hockey match.
I'm often asked about HD on TV over IP. The reality is that it exists now, but again, is a virtual concept since most domestic PCs aren't powerful enough to decode the stream - even if you have enough bandwidth to deliver it in the first place. But, is 2Mpbs HD, or does it need to be 8Mpbs? Uncompressed, HDTV is 1188Mbps - but I doubt if anyone is delivering this! It does make me wonder what data rate you're actually being delivered to your TV when HD is served. Consensus has it that around 20Mbps is being used.
Bigger screens, bigger pipes and adaptable standards are the way we will see the TV future.