Turns out that something at our provider went kablooey. As such, for some people, the site is being reaaaalllly slooooow. For others, it's fine. For example, it's pretty peppy for me, but I pinged a couple other people, and it's sluggish for some. A fellow admin who also uses the same provider has lost access to 2 of 5 machines, so there is definitely something up. More info as we get it.
Sorry for those that this affects, but it is something that is out of our hands. If this is still going on tomorrow morning, I will increase my annoyance-making at our provider!
Thankfully, it has nothing to do with the site upgrade. Then we'd be really busy! :)
Engelbart D. Mouse