Turns out that my massive Outlook pst file wasn't being archived correctly. I thought I had it set to sweep all emails older than 6 months to an archive folder. But, only the top level folders were being dumped.
And, I found Attachment Save, a great utility from Sperry Software that moves all my attachments into the file system in the same folder structure as my Outlook folders, eliminating oodles of space in my pst files. It even provides a link to the attachment in its new location, making it just as convenient to open files from emails as it ever was. AND, if you forward an email with an attachment, it's smart enough to go get the attachment from the file system and attach it to the outgoing mail. Snazzy.
Oh, and one more thing: I had a auto sync going on between my CardScan database and Outlook that was really hosing performance. Got rid of that process too.
And life was good again...