WPF

WPF(Windows Presentation Foundation) is the engine that is responsible for creating, displaying, and manipulating user-interfaces, documents, images, movies, and media in Windows Vista and upper versions.


Physically, WPF is a set of libraries that have all functionalty you need to build, run, execute, and manage Windows Vista applications.

Expression Blend
Expression Blend is mainly for the ponytail set (artistic types who prefer Macs) to create vector-based, animated, and three-dimensional graphics — much the way they do in Photoshop. Blend has a rich set of brushes, palettes, paint buckets, text, gradients, timelines, and event triggers for those with the skill to take advantage of them.
The XML-based files that Blend generates work in Windows Presentation Foundation (WPF) applications that run on Windows and in cross-platform Silverlight apps for the Web.