C# v3.0 - Visual Studio 2008
Windows Presentation Foundation (WPF)
A new user interface subsystem and API based on XML and vector graphics, which uses 3D computer graphics hardware and Direct3D technologies. See WPF SDK for developer articles and documentation on WPF.
Windows Communication Foundation (WCF)
A service-oriented messaging system which allows programs to interoperate locally or remotely similar to web services.
Windows Workflow Foundation (WF)
allows for building of task automation and integrated transactions using workflows.
A software component which securely stores a person's digital identities and provides a unified interface for choosing the identity for a particular transaction, such as logging in to a website.