I started off with 02 and upgraded to 04, but had to reformat my HD and I'm back to 02. Since I don't use it I didn't see any reason to throw in the upgrade. From what I see it's XP Pro with some added features. When $$$ are available I'm going to build a HTPC next and I'll probably use it then.
Besides the mentioned video error it doesn't play Divx files even though it shows a thumbnail of the video. I get the error "Video cannot be viewed in Media Center from a Remote Desktop Connection." Problem is I'm not using a RDC.
BTW I don't believe I mentioned how I got a copy