worked in sane - could have done with that earlier.
You would really want to chgrp /dev/sg3 scanner to get the entry how you are used to - do you still have a "scanner" group? What did you change the ownership to? (This helps others understand your problem.) Basically all that happened is that the scsi scanner did not get assigned to the "scanner" group. As you discovered, going through each scsi device separately to work out which is the scanner is the fix. scanimage --list-devices also reveals scsi scanners.
mounting flash card:
Is this *all* removable drives or just flash cards?
... in ubuntu you open gconf-editor and look for /apps/nautilus/preferences/media_automount and set the automount key to "true". set /apps/nautilus/preferences/media_automount_open to true to if you want nautilus to open a window for the device.
... but for debian-wheezy, there is sometimes a problem:
- I know it says xfce but neither issue in there turned out to be an xfce problem.
... do you have a default install (eg. what were your install options?)
... check you have udisks, gvfs and libpam-ck-connector installed... also look for the command= line in the gdm configuration.
(eg. read through the whole bug report.)