Click on this link for the poll.
Add the Date Completed Field When Logging Tasks for Leads
When working with Tasks and Lead records, it is necessary to view the Due Date and the Date Completed fields under Communication > Activities tab. In the Default view, the given Date field is the Task's Due Date.
To display the Date Completed in the Custom View, create an Activity Saved Search and add the Date Completed field in the Results tab.
Custom views allow you to view a list based on the results of saved search criteria.
I hope this helps.