I noticed in the SharePoint designer 2010 workflow some OOTB task actions options are missing.
SharePoint 2010 Enterprise edition...
Append task, Delegate Task, Escalate Task, Forward task.
Although they are OOTB actions, they are not available in every context.
Not too informative, but still accurate quote from SharePoint Designer 2010 reference guide:
The actions available in the category vary depending on your context in a workflow.