So, it sounds to me like XAML and Avalon will make designing a Longhorn client app very similar to designing and ASP.Net web application.  With the option of embedded code (in the markup) or code behind, and the markup defining the visual interface.

This is interesting and sounds cool, but I do have a few questions:

1.  Is my analogy correct?  Please give any comments correcting or extending this line of thought.

2.  Along the ASP.Net lines, most objects are server side, running in .Net.  If this is possible with Avalon (to some extent), does this mean at some point Longhorn apps could end up running in any compatible browser.  Markup + classes on the server (like ASP.Net) sounds like it would enable that...assuming MS published what would be required.

3.  If Avalon will be part of .Net, could it eventually make its way into the Mono project (or similar) (parts of it anyway)?  Would XAML be a public spec that could be used by others?

4. How would designing GUIs in XAML affect application performance?  Would it make it like rendering a web page locally (slow, but acceptable)?

Anyway, it's interesting stuff.  I look forward to reading your comments.