I'm really, really glad our team did the work to make these publicly available. The Media Center Diagnostic Tool gathers a lot of pertinent information very useful to the team in troubleshooting issues with Windows Media Center. If you ever file a bug report during the beta or are working with someone at Microsoft to determine what's happening it's a good idea to have these tools installed and take a snapshot of your system to share with the person helping you.
Media Center Diagnostic (MCDiag) Tool [x64]
Media Center Diagnostic (MCDiag) Tool [x86]