Okay. This is a big one. This morning, we released the Expression Interactive Designer January 2006 CTP (formerly known as "Sparkle"). This build runs on both the December 2005 and January 2006 CTPs of WinFX, and as a point of interest, the tool itself is written in managed code and uses WPF for its user interface (check out John Gossman's PDC talk for technical details on how Expression Interactive Designer was built). Unlike "Cider," whose primary audience is a developer working inside of Visual Studio, this is a standalone tool that is targeted primarily at designers. Of course—this being the real world—we realize that the skill set between developers and designers is a continuum, so I expect that Expression Interactive Designer will be interesting and useful to almost anyone involved in the development of WPF applications (this means you).
Here's a list of resources that should be useful as you investigate this new release:
I'd also like to point out a brand new version of Electric Rain's excellent ZAM 3D tool that works with Expression Interactive Designer. You can find it featured on our Partner Tools page.