I am certainly staying away from Silverlight. Microsoft has shown (and now said) that it plans to discontinue development. Plus, let's be honest, it was never popular. I can count the number of sites on one hand which use/support it.

Plus HTML5/CSS3 is doing some very cool stuff and is more or less designed to replace Flash (and by extension Silverlight). If I write something for HTML5 today I can be reasonably assured that that investment will be worth something in 5-10 years, Silverlight might not be installed on people's computers in that time.

Microsoft should have released Silverlight has a "free alternative to Flash" then made Windows development tools entirely free, and the framework completely open source. Problem is that Microsoft doesn't understand the nature/ecosystem of free/Open Source things (for example it doesn't accept patches, bug reports, or feedback of any kind).