I've been playing with Silverlight for perhaps 2 weeks now. Evaluating it for a business application, here are some findings:
Silverlight 1.1 (now renamed to 2.0) Alpha
Programming with managed code is awesome. Lack of standard controls really sticks out at you, everybody is writing their own versions of TextBox, DropDownList, etc etc. No Cross-Domain web service calls is annoying too. Writing XAML in Blend is a lot easier than in VS.NET even with the Silverlight tools installed.
Silverlight 2.0 Beta
Apparently this will be released in a few more weeks' time, before MIX 2008. It's got everything. More controls, better network stack. All for under 5mb download. Go-live licence.
I'm somewhat annoyed they won't allow sockets - I want to write a game :-(.