Strangest problem, but I have had intermittent crashes in 10.4.8 and 10.4.9 when copying pictures from either a 2gb Sandisk mini Cruzer usb drive or copying pictures from a Verbatim multi-card reader (I've tried two models) using either 1gb compact flash or an SD card. The real rub is that I have had these crashes with both a PBG4 and a Macbook in 10.4.9.
The copy progress bar stops part way through and the Finder no longer works. I can quit other programs, but I can't quit the Finder (even force quit won't work). I have to then hold down the power bar for the Ugly Shutdown. It usually works fine after the restart. It sometimes works a few times over the course of a few days before failing.
I can't find anybody else with this problem through all my googling, but there must be someone out there...