Not sure if this has been mentioned before.. But.. While I like the idea of the 'trashcan' in IPB, I actually preferred the concept of 'soft-delete' in vB. Basically, it marks the post as deleted, it allows you to record a reason, etc.. mods/admins can still "see" it, but to everyone else it's gone. Benefit is that it's in the "right place" if another mod/admin decides to un-delete the thread/post. It's quite handy IMHO.
One other thing that's nice to have.. The ability to download (easily) a list of all the emails address for users on your board. Allow to be sorted by 'allow emails from admins', etc.. Right now there's no easy way to do this without MySQL queries.