I was putting off the 2.5 upgrade for WordPress for a few days, then I saw a list of the security issues it solved, and figured that I may as well go ahead with it. The upgrade was smooth and clean, as usual, and the look-and-feel changes in the admin area are going to need a few days.
The docs page at WP says that the admin area is totally widgetized, so I may be able to tweak the placement of things to an extent. The important thing is that the upgrade was minimally invasive, quick and relatively painless. All of my plugins seem to be working without a hitch, and I think that the load time of my homepage may have dropped by a couple of seconds, too. Bonus!
(Not actually disgruntled.)