I have a Pismo G3 PowerBook that was on (and plugged in) before, during, and after a short power outage in my neighborhood this morning. I don't believe the outage lasted long enough for the battery to have drained, but I'm not sure, since it happened after I was at work for the day.
Since I got home tonight, the thing has been crazy unstable. I've had to hard reboot multiple times, and at least twice was greeted with a broken folder icon after hard rebooting. Option+Boot to make it boot the OS 9 volume works, at least.
I've reset the PRAM, as well as pulling the battery + power and letting it sit for about ten minutes without power. I haven't had problems with this machine at all, so I'm wondering if the power blip was responsible for something getting corrupted in the OS.