What STB output are you considering for this?
The component output is analog (though good quality and HD) but has too high a data rate to be taken into the PC. We are all waiting for a PCI card that will take HD component input and compress it (encode) in hardware for storage and playback.
The DVI output: I have yet to see a DVI input on a PC and data rate is again a problem not to mention HDCP.
That leaves S-Video which a lot of us are doing but this is low res (Std Def; SD) so no great shakes.
The only other way of getting HD content into the HTPC are ATSC OTA tuner cards like MyHD and unfortunately the BC (Broadcast Flag) is coming for that next year though currently being challenged in court.
This firewire link offers the only way to get compressed, digital HD from the STB to PC but has the DTCP (Digital Transmission Content Protection) ax hanging over it. Sadly for this reason, it is doubtful that this will be anything more than an experiment.
You can thank our esteemed legislators for all this BS.
EDIT: I should say "affordable" PCI card with HD component input. There are some professional very high dollar cards that can take HD component input. You will find some affordable cards that take component input but if you read the fine print you will find they are limited to SD resolutions such as Holo3D. Check this thread for some intitial excitement due to some false claims made by the marketing writers of this product with regard to the component input: http://www.avsforum.com/avs-vb/showt...ight=s3+chrome
. The thread will now sink into oblivion since the truth is now apparent (no HD).