So during my free time this holiday I built my own Media Center PC using an old Dell 8000 1.4 ghz, ATI All In Wonder 9000 Pro grahpics card and ordered a Phillips remote from new egg to drive it. About 30 hours later and 4 installs of Windows XP with the MCE overlay I got it working. For the most part anyway. The remote works flawlessly, I can play Videos and Music from my media library. The only thing left to get to work is the ATI card. For right now, it is exactly what I want. I have Tivo, so I don't care about recording shows from the MCE at this point.
First, this is only possible if you have an MSDN subscription, and the ability to download Windows XP MCE. Otherwise only OEMs have the ability to build the Media PCs.
Couple of headaches during the install:
The serial key identifies to the XP install that you are doing an XP MCE install, not just an XP Pro SP1 install. This took me a couple of tries to actually figure out.
Once I got it installed, I got the infamous Video Error. I had to install the ATI DVD codec and WinDVD in order to get MCE to play DVDs.
As I mentioned before, I have not tried to get the ATI card to play TV inside of MCE. I have done some research on it and it looks like you can do it. Dell is using the ATI card in there recently released Media PC, and I have seen some instructions on their forum on how to get it to work...