Well, that was an exciting announcement.  There’s a good CNET interview with BillG that provides insight into the decision.  Here’s my perspective on what happened

We’ve gotten a lot of feedback from customers about WinFX.  Among the things we heard:

• Indigo is great, but I need to use the same communications API for all my apps, whether they’re LH, XP or Server.  Don’t make me use Indigo for LH and WSE for XP.
• Avalon is great, but I don’t want to have to build a separate WinForms UI for my XP apps and then some different Avalon UI for LH
• It will be a while before the majority of our customers are running LH on their desktops.
• I wish I had WinFX for the app I’m building today!

So we listened, and did some thinking.  We concluded we could meet the bulk of our customer needs by releasing WinFX as quickly as possible, supporting XP and Server 2003.

We also recognized that doing this would likely delay parts of WinFX that were planning on taking advantage of new features in LH (like WinFS...more to come on the subject in the next post,) but the value in releasing a subset of the original LH vision as quickly and broadly as possible outweighed the cost of deferring the full implementation

The upside to this plan is huge.  Avalon and Indigo available on XP?  And in 2006?  That’s really just fantastic news.  I can tell you that I am certainly excited about no longer having to speculate on when we’d have enough Longhorn desktops to justify taking a dependency on WinFX.