For some reason, within the past couple of days Netflix streaming in our Vista Media Center stopped working. The interesting thing is that playback worked from the browser and from PlayOn, both from that computer. Nothing that I did solved the problem. I was getting so frustrated that I wanted to just get a Roku HD, so I wouldn't have to deal with software configuration anymore.
As one last ditch effort, I wanted to upgrade to Windows 7 to see if would fix Netflix streaming. If it didn't, I would go get a cheap Comcast DVR, and a Roku HD box for each TV.
The upgrade to Windows 7 went smoothly, and I am now able to stream Netflix content. Also Windows 7 Media Center adds other Internet TV sources. In addition to those things, the redone UI is very nice.