The PC as a Media Center
It's an idea whose time may never come. Not that there aren't a lot of techies out there trying to get it to work, but those guys are, by definition already way deep into pain and suffering, so they don't count. Just try and get a tuner that can handle 64b QAM and 256b QAM, let alone one that handles the encrypted versions of Qam. Then there are the problems of getting the right antenna for ATSC broadcasts OTA. You have to be a masochist of monumental proportions to go there.
Really though the problem isn't technical, but the usual culprit, greed. All the content providers including the cable COs, the satellite guys, and the telcos aren't satisfied with supplying you a pipe into the Internet, they want to control the content as well. You having a PC based system that bypasses the need to have a STB for time-shifting etc. is anathema to them. The studios and recording companies wholeheartedly support that scheme as it reduces your ability to copy, timeshift, or alter the data sent to your home in any way without paying and paying and paying for the privilege. In the DRM model being pushed we're all going to be helpless droids restricted in our viewing to whatever we can pay for and to whatever they communication guys want to provide.
There is a ray of hope though. That's WI-Max, which has the potential to bust open the monopolies and allow us to access the Internet directly. Why should I have to restrict my viewing to just what the cable/etc. guys want to provide. Why shouldn't I have the right to access a URL that is showing the same movie but for less? And why shouldn't I have the right to copy a television show to a DVD or HD disc for later viewing or retention?
What's needed is for communities to erect the towers or have ISP’s that aren't pushing programming do so. One other possibility is that GOOGLE may opt to do so. This would probably be the best way to go as GOOGLE has the cash to buy the bandwidth needed. Trying to use the unassigned bandwidth would probably be a problem, but if the towers were close enough and the range restricted enough that could also work.
Anyway, if you just want to watch NTSC television and DVDs a media center PC will work, but forget about HD, at least for the time being, unless your OTA reception is very good. If you have to have HDTV for now you're better off going through your cable/etc. provider.
Still you've got that box of remotes and software that's so primitive it's just this side of chiseling in stone. The whole thing is just a mess and liable to stay that way for some time, but the allure is so great that it's amazing what people will put up with. I can hardly imagine what it will be like when they get holographic TV to work.
