OH... and just an aside here.....there is no way in h&ll I'd pay top dollar for a high end system and Windows Media Center when this setup works absolutely flawlessly, and will run on a hand-me-down computer. If you have any technical knowledge at all, this is the way to go.
I'm pretty proficient with linux - I have fedora core 2 running now and know the linux internals fairly well.
Right now my main TV has a timewarner DVR - scientific atlanta. For "Production use" I will likely stick with that for now - it might be fun to try to build mythTV for my non-main TV as a fun project - does one need digital cable as input or can it use analog? Does it need a phone line? Where does it learn its programming guide info? From the cable companies feed? Doesn't that mandate a digital cable signal coming in? Thanks.