One of the great things about Windows Workflow Foundation is the support for declarative no-code workflows that reference pre-compiled workflow activity libraries.  With enough of these activity libraries in place, you can use SharePoint Designer 2007 to build some pretty powerful applications without writing any additional code.  But it also presents a kind of chicken-and-egg problem.  You first need a bunch of quality activities you can stitch together using the declarative tool.

Ryan Miller has published a set of Workflow Activities that you can install on a SharePoint server and then use them from SharePoint Designer to manipulate sites and site collections in ways that go beyond what the out-of-the-box activities allow you to do.  He presents them in a codeplex projectthat contains two categories of activities: site management and list item management activities.

The site management activities include things like creating sites and site collections, setting the site title and theme, activating features and manipulating site groups.  At the item level, there are a couple of unique activities for copying, updating and removing list items.

Check them out.