Now that we have released Workflow Studio 1.1, I wanted to point out that we also have articles with details about what is available in each activity library. There are 8 different libraries listed in the installer – click on the item below to view the activities available with each one:

Note: The Group Policy activity library requires the Microsoft Group Policy Management Console (GPMC) to be installed before it can be used. You can get GPMC here:
http://www.microsoft.com/downloads/details.aspx?familyid=0a6d4c24-8cbd-4b35-9272-dd3cbfc81887&displaylang=en