WinFX January CTP Released
WinFX Runtime Components - includes everything you need to run WinFX applications
Go-Live licenses for WCF and WF - if you want to deploy WCF or WF applications in a live operating environment (see Arik Cohen's post about why WPF doesn't have a Go-Live license for this release)
Windows SDK - for the developer documentation, tools, samples, etc. (see uninstall note below)
Microsoft Visual Studio Code Name “Orcas” Community Technology Preview - Development Tools for WinFX® - adds IntelliSense, new project types, and "Cider" to Visual Studio 2005
Visual Studio Extensions for WorkFlow - if you're developing WF applications
WinFX RC January CTP “Readme” - you read these things thoroughly, right?