Doug-
Great post. The main problem is that for many people, Exchange has become their file system. The metadata that consists of the message and attachment combined is too valuable to split by saving attachments to a traditional file system. SO and other legal constraints have only made matters worse forcing some of us to retain messages for an insane period of time. It would have been nice if Exchange 2007 had an archive database built in that would move messages out of the main store automatically after certain criteria was met. It would also be nice if Outlook 2007 had a more efficient compression engine so that OSTs were as small as possible, but I understand this could cause performance issues.