Fifteen Cool Features in WPF 3.5

re's a non-exhaustive list of improvements:

• Performance
• Fixed animation glitching issues.
• Layered windows are now hardware accelerated.
• Many other fixes to improve cold start, data binding, etc.
• Data Binding
• Support for XLINQ binding.
• Improved data validation on binding (ValidatesOnDataErrors and ValidatesOnExceptions binding properties).
• Much better debugging (PresentationTraceSources.TraceLevel can be set on bindings or providers).
• Graphics and Text
• UIElement3D (enables interactive 2D content on 3D surfaces).
• Improved support for IMEs (input method editors).
• Indic script support.
• TextBox now supports a limited undo history.
• RichTextBox now fully supports inline elements (e.g. a Button).
• XBAPs
• Introduced support for the Firefox browser.
• WCF now operates in partial-trust mode.
• Can now read/write HTTP cookies.
• App Model
• System.AddIn provides support for isolated visual and non-visual add-ins, allowing for discovery, versioning, activation and lifecycle management.