I just wanted to post here a warning for any Slow Travelers who might have an Apple Airport Extreme Base Station for wi-fi. My sister just got a notification of a firmware update for that base station, and when she downloaded and installed it her Airport stopped working. So she can no longer get on the Internet, except by plugging one computer into the DSL modem with an Ethernet cable -- i.e., she has no wi-fi any more. We have since checked the Apple support forums and see that many other people are having the same problem -- both with the Airport Extreme and with the Time Capsule.
So ... just in case it might help anyone here, I thought I would share this.
In fact, my general rule of thumb when I get those popup notices of updates, is that I never install them right away. I think it's always safest to wait a few days, because fairly often there are reports of problems and the initial update is pulled. Apple has a very active support forum, so you can always go there and see if other people have reported problems.