I would love to be able to do a mass delete action on my inbox, but mass "mark as read" or "mark as unread" would be awesome too. Mostly the delete though. I have a couple hundred I need to delete and to have to delete (and confirm!) each one makes it a rather daunting task that I keep putting off - so I'm pulling those msgs every time I open my inbox.
eta: Because I am insanogirl, I just timed it... it takes about 7s to delete a message. To delete 200 would take 20-30minutes. Nuts to that.