.NET Framework 4 and VS Beta1 docs are posted
The new data binding builder in the WPF Designer and the Silverlight Designer
You’ll see the strong focus on line-of-business (LOB) applications in this release. In particular, binding WPF and Silverlight apps to enterprise data sets is supported in the WPF Designer: see Binding WPF Controls to Data in Visual Studio and Walkthrough: Creating a Data Binding by Using the WPF Designer for details. You’ll notice other improvements, including new LOB controls such as DataGrid, DatePicker, and Calendar.
DataGrid displaying an AdventureWorks data set
And consider spicing up your WPF and Silverlight animations with the EasingFunction classes. They pack a lot of functionality into a tight package.
BounceEase easing function