I just want the premium channels (and possibly digital!) I get with my cable box on my PC. Anybody know if tis’ all possible?
Not currently. All of the cable companies use proprietary encryption on their digital channels (which is anywhere from channel 60-100 and up). The encryption is not trivial (it's not impossible either), and breaking it would be a violation of the DMCA. AFAIK, nobody sells boxes (even set top ones) that can decrypt the encoding because it varies from market to market (and a single cable company in one city may even have multiple encryptions from area to area, depending on if they bought out other companies to get the subscribers).
Now, that said, this is due to change. The OpenCable standard is supposed to take effect on July 1 (or thereabouts) of this year. At that point you should be able to go buy your own set top cable box, PC card, or TV and slip in a crypto card from the cable company. You won't have to rent the box anymore, just the card... although don't be surprised if it's still $5+/month to get the freaking card.