Roger,
When ingesting images from a cf card I tryed both USB and firewire 16gb took almost 1 hour
Another user reported a similar issue. Rebooting 10.6 made the problem go away.
We have some Firewire readers that 10.6 recognizes but refuses to mount cards on. This reader is no cheap reader either. It is a Lexar RW019 model which for a couple of years was the best reader around.
I'm sure some of this will be sorted out in an update from Apple to Mac OS X 10.6.
-Kirk