There are not yet any digital/HD tuners available in PCI-E, though there may be one coming soon (actually, it was supposed to already have been released, but I haven't heard anything about it lately). For PCI, you have a few choices...will you be doing only OTA/antenna reception of HD channels? Or will you want to receive (unencrypted) digital/HD channels over cable as well? ATI has the HDTV Wonder, which I have no experience with and only works for OTA digital/HD (and analog cable, not digital). Then there's the MyHD MDP-130 and DVICO FusionHDTV 5, both of which can also receive unencrypted digital/HD cable channels - I have the MyHD card myself, and I'm very happy with it. The Fusion card is pretty decent too, and cheaper. Both will allow you to record and timeshift, although the Fusion card seems to have issues when timeshifting cable. There are one or two more cards out there, but I don't know much about them and haven't used them myself.
If you have more specific questions, feel free to ask and I'll try to answer...(if I remember to check this thread again

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