[Stephen Lowe]

I like Flash.
But Silverlight's got two big advantages for me, even though I already know Actionscript.

1. There are a lot more people around here who know C# and VB.Net (a lot of the web development projects I work with are hosted on ASP.NET) than know Actionscript. Since you code Silverlight apps with (pretty much any) .Net language, this is pretty helpful when the alternative is learning Actionscript or hiring more staff.

2. Both content and Metadata in Silverlight are stored in XAML. XAML is searchable, so seach engines crawlers are (will be?) able to search Silverlight content. Flash, on the other hand, is opaque to web spiders and crawlers.

Another advantage I'm starting to see is that Silverlight is WPF light, so there's a high degree of portability between a desktop app and a Silverlight web page. Since the programming model is strictly event driven (no need to deal with postbacks), Silverlight development can be done by developers with a desktop background and next to no web experience.

Stephen Lowe
(disclaimer: though I work for Microsoft as an Architect Evangelist, my opinions (and occasional errors) are my own.