I guess the hardware requirement(s) answer would be, check on Ubuntu and MythTV. 

But...

If this thing is going to take off, a few choices for minimum level hardware pieces is absolutely imperative.  I am a Windows Media Center fanatic, but I'm ready to give this a try right now.  But...  Only once the powers that be who want to put this application on top will compile a recommended hardware list.  I can't/won't spend time and money to find out that a capture card won't work, or that a video card has crappy driver support.

You may rename this thread "Desperately Seeking Recommended Hardware" if you like.

Maybe I'm missing WHERE the recommended-hardware/minimum-hardware requirement list is located?

Also, playing High Def usually takes more resources than 480p or 480i.  I'd like an idea as to what kind of CPU/Memory will be needed.

Cliff