Just a follow up, I don't know when "Next" is coming out. I'm starting to have a feeling it may be released about the same time as Longhorn and XB2 (~2006).

The other features mentioned are all supported under DX8 (better shadows, 8+ light sources, etc.). In fact, one of the benefits of the XBox's fixed hardware is that a lot of developers are spending much more time with DX8 then the previous DXs. As a result, there are a lot of more tricks and a much greater understanding of DX8's strengths and weaknesses.