The best all-up run-down of all the features (WPF, ASP.NET, WinForms, VS etc.) can as ever be found on Scott Guthrie’s blog: http://weblogs.asp.net/scottgu/archive/2008/05/12/visual-studio-2008-and-net-framework-3-5-service-pack-1-beta.aspx Pretty comprehensive write-up of the WPF-specific features here...
This release extends LitwareHR, reference S+S application, and provide guidance on the full spectrum of S+S (Client, Server, Service). Based on frequent requests, also included in the release is a new Multi-Tenant Database Performance Guide, which provides tests results and guidance to compare the performance...