Partial solution in the workbench module that allows you to delete media. Whole objects means node and media. No current one step solution. This probably also implies the idea of finding and deleting orphaned media.
When you want to delete an object you have to delete media first before node. Workbench logic does not work for our case where the node media relationship is separate. Two pieces:
Implementing a delete option in workbench
Creating a standard view reporting orphaned media and unattached files (Views Bulk Operations view)
Partial solution in the workbench module that allows you to delete media. Whole objects means node and media. No current one step solution. This probably also implies the idea of finding and deleting orphaned media.