Well, Troy beat me to the punch, but I might as well post anyway. You can get a copy of the PowerPoint deck I used at PDC05 for PRS322 Windows Vista Media Center: Developing for the 10-Foot Interface, a high level introduction to some of the features we are adding to the Media Center platform for Windows Vista.
I also recommend a couple of the other presentations from http://commnet.microsoftpdc.com/content/downloads.aspx for you to get a more complete picture of the development platform for Media Center in Windows Vista...
The Hosted HTML model isn't going away for Media Center developers in Windows Vista, and Michael Wallent's talk helps you decide which is the best approach in PRS200 Choosing the Right Presentation Technology: Windows Presentation Foundation ("Avalon"), Windows Forms, ASP.NET, IE, and More. Furthermore, the ASP.NET 2.0 team tells you how to get the most out of targeting HTML in PRS312 ASP.NET: Future Directions for Developing Rich Web Applications with Atlas (Part 1) and PRS420 ASP.NET: Future Directions for Developing Rich Web Applications with Atlas (Part 2).
Robert Ingebretson has a must read PRS317 Windows Presentation Foundation ("Avalon"): Beautiful Code, Beautiful Design - Applications Your Designers Can Work With. Memorize this deck and you will be well prepared for creating wonderful experiences in 2' and 10'. And don't forget his demo deck for the presentation.
PRS324 Windows Presentation Foundation ("Avalon"): Using Data in Your Windows Presentation Foundation ("Avalon") Applications: XML, Windows Communications Foundation ("Indigo"), ADO.NET and More will help you wire up the great graphics and UX to the underlying data.
For those of you who want the nitty gritty, check out PRS435 Windows Presentation Foundation ("Avalon"): Going Under the Hood to Understand the Architecture and PRSL05 Case Study: What We Learned Building Project Max on WinFX are invaluable.
These presentations will give you a great introduction and begin to build your foundation for Media Center design and development in Windows Vista.
And there is still more to come...but I can't talk about it just yet...you're gonna love it...