Well just have to see what happens with that one. If you are talking about pay cable television, you most liklly already have digital tv. Your cable box converts it from digital to analog and will continue to do so even after that date so nothing will change and your current equipment will work just fine after 2009. What is effected is brodcast tv. If it actually does happen, brodcast tv will all be digital and your equipment must have a digital tuner or no free over the air brodcast tv. I say if it does happen, because it was suposed to have already happened (it was set into law back in the 90's), and if I am not mistaken, they have already pushed back the deadline twice (the 2009 deadline would be the second time they have pushed it back). They also are claiming subsidies to provide free digital to analog converters to those still using analog tv sets. I think the current planned subsidy is something like 40$ or 50$ for a converter and you can get 2 per household. It would be funny if half the nation requested two converters. That would be somewhere along the lines of 2 billion dollars in subsidies. If it happened, I'm betting the deadline would get pushed back yet again, but eventually it will happen (when most Americans have switched to digital equipment on their own).
I suspect that blue laser formats will be the same. They cannot force it down our throat (they cannot make us buy stuff) and dvd will be alive for a long time. Movie companies will not stop producing dvd's if that is where the sales potential is and if there are not enough consumers that use blue laser players. Hardware manufactures will not stop producing dvd equipment if that is what people are still buying (they are not going to just throw away all the sales to other companies that still make dvd ewuipment). Rental companies will not stop renting dvd's and stores will not stop selling them if that is what the consumer is willing the shell out the money for. It will eventually happen, but who knows if blue ray or hd will even be the formats to do it. Personally the drm/broadcast flag type of things included with these formats is enough to make me never upgrade and I know at least some other people feel the same way (though they will probably crack it all in no time).

I wouldn't worry too much about being forced to upgrade. It wont happen till the equipment is so cheap that everyone can easilly afford them (like dvd drives/player are now, 30$). Dvd still hasent even killed cd despite the low cost (though they are working on it).