The spiffy new SL2 doc set is live on MSDN. Be sure to check out the new QuickStarts, which show you how to play with things like Deep Zoom and Isolated Storage.
Animations Describes how to create basic animations by changing property values and by using key frames.
Audio and Video Describes how to integrate media into your applications.
Images Describes how to integrate images into your applications.
Gratuitous Deep Zoom-ready image
Deep Zoom Describes how to create a Deep Zoom image, load a Deep Zoom image, and add interactivity.
Control Templates Describes how to create a ControlTemplate to customize the appearance of a CheckBox control.
Data Binding to Controls Describes how to data bind to a control and customize the display.
Image data saved in isolated storage
Isolated Storage Describes how to save and retrieve data as key-value pairs or files in isolated storage.
LINQ to XML Describes hows how to use LINQ to filter, group, sort, transform, and project an RSS feed.
Syndication Feeds Describes how to create a Silverlight client that can access and display a syndication service.
Web Services Provides an introduction to using Web services in Silverlight.
Dynamic Languages Demonstrates dynamic languages (Python and Ruby) by showing the DLR Console sample.