Saw this forum post, and thought it worthwhile to send out an FYI to the rest of the world:
In Silverlight 1.0, we use Lucida as the default font. For Silverlight 2 apps, we created a world-friendly font, called the Portable UI font (PUI!), which uses the Verdana glyphs for the Western characters and a variety of other glyphs for other languages.
Why? SL1 needed a web-friendly font. SL2 wanted to ship a font that looked great with our controls. The decision to use Lucida and Verdana depending on whether you host CLR was a compromise that I brokered between our designer, the text team, and the compat folks.
If you find yourself in a jam where you need to match the standard Silverlight 2 font, set the FontFamily to Verdana at the top of your application. If the characters are Western, we will use Verdana. If the characters are not supported by Verdana, it will fall back to our PUI.
(The issue in the linked post is a bug, we should detect that it is a Silverlight 2 app regradless of the extension. Let us know if you see any other variants of this bug, would love to hammer those out.)