I enjoyed the PRS200 talk yesterday about the various presentation choises that are available / coming.  Atlas is truely awesome..  applying the ASP.NET principles of encapsulation and rapidity / easy of use to what has traditionally been a minefield for developers is very cool..  auto JavaScript object proxy generation is priceless; I quickly foresook the obvious user benefits of the AJAX approach for the productivity of ASP.NET years ago with a lingering regret that the user experience was downlevel.  Now I can do both. 

I only wish Scott Guthrie (PUM for ASP / Atlas / IIS) was involved in helping to shape Avalon into something more developer friendly; I resonated completely with the first question posed to Rob Relea after his RPS305 lap around Avalon talk:  "From a developer point of view it looks like a nightmare".  Yes it does.  And Orcas is a long, long way away.

That said, it was intereting to learn more about WPF/E..  basically a portable implementaiton of Avalon that will run cross platform.  The pic taken in PRS200 shows a Mac rendering a XAML file.