I've heard requests for chats on Media Center. Not sure if you everyone knew about our chats or not but we do hold chats pretty regularly (I attend when I can). People from the product group and MVPs participate to help you with any issues you have.
You can get more info at: http://www.microsoft.com/windowsxp/expertzone/chats/default.mspx
Thanks for all the suggestions below. We are working on making it easier to get info about Online Spotlight for the Vista timeframe and we're doing a lot of work to make it better.
In terms of the Media Center platform I'm working on some community stuff that will hopefully make things better for enthusiast devs as well as others. It might be a bit of time but I'll announce plans here. 🙂