First off, after happily downloading the new version, I started reading the WordPress support forums to see if any common installation problems were cropping up. Good thing I did, too, because the minimum PHP/SQL requirements were increased for this release (and this critical information was - shall we say - not exactly made obvious in the version announcement and upgrade information).
I checked my server, only to discover that I was running older versions of both PHP and MySQL. Fortunately, I have an awesome, responsive host, because all it took was a request to upgrade PHP/MySQL, and they took care of it in less than 24 hours.
Unfortunately, upon upgrading, some of you may have noticed that the blog disappeared completely. As it turns out, my WordPress install with all of the plugins I'm using had gotten a bit bloated with PHP memory use. I had to disable several plugins temporarily to get back under the max PHP memory allocation. (Again, a support request to the host to increase the max memory allocation was responded to promptly, and the request should be taken care of sometime today.)
Having taken care of those issues, I went ahead with the upgrade last night. I probably should have done a bit more research, as the upgrade involved quite a few fundamental changes to the back end, including template tags and other gotchas. So, I've spent most of last night and this morning making several underlying changes to my blog template (the details of with which I will not bore you). Things should be working properly now, but if you notice anything broken or amiss, let me know.
Update: I'm glad to see that someone found some usefulness in this post!