The ExtremeTech Podcast for last week was an interview with one of the DirectX 10 architects, David Blythe, and Chris Donahue who is on the Biz Dev side of the house. The interview covers the new graphics architecture in Vista as well as what has changed for DX10. There is a lot of useful information in this interview. You'll get the most out of it if you have some understanding of how graphics pipelines work already but it doesn't get too deeply technical. There is a lot of exciting stuff made possible by the more generalized shader model and the new geometry shader in DX10.
We don't do a lot of DX10-related work here in video land but do rely heavily on the new Vista display driver architecture (WDDM). Here is a presentation David gave at WinHEC a year ago on the subject. If you are curious, much of what I work on in the video realm falls into that box labeled "DXVA." You can learn more about it from this WinHEC presentation given by Rodolfo Vargas, a PM that I work closely with.
Let me warn you that the sound quality of the interview is terrible. If you don't want to suffer your way through it, there is also a transcript of the interview available here.