i think if you call sky you can blag a sky+ box for cheap (about £40), NO extra subscription a month and might even be able to get half price subscription for 3 months!!!
as for the HD tv nonsense, you`ll need to pay extra for the channels no doubt + will need an HD ready TV.
as for the standards, i`m a bit shakey on this, but i think you got 3 outputting standards and 2 source standards....... pretty much everything will run from a 720 source with the 1080i using the 720p as a sourch of info....
1080p stuff will mainly be restricted to movies releases and stuff and as far as transmissions stuff goes, probably wont ever happen, as was already said, 1080p TVs cost a small fortune!!!
i`m gonna wait til theres more stuff using all this new fancy technology that seems to be coming out of everywhere, let it all calm down as prices on stuff shouldn`t be too militant then either!!