WinFX September CTP is out!
The team has also made sure the platform is secure and more stable & performant than it has ever been. That focus on improving the fundamentals remains an ongoing exercise, until we release to market (RTM).
As always folks on my team and I are asking people to give this a whirl and tell us how we are doing and where we can improve. You can leave a comment here or better still post them to the Windows Presentation Foundation newsgroup.