I decided to try the prescription from the thread on gdm chooser for turning off the user list:
GCONFSYS=$(gconftool-2 --get-default-source) gconftool-2 --config-source=$GCONFSYS --set /apps/gdm/simple-greeter/disable_user_list --type bool true
It did indeed work, no more stoopid user list, but as a side effect it also utterly ignored my ~/.dmrc file.
It always defaults to a GNOME session login, I have to manually pick a different session kind on each login - the choice does not stick.
It is really too bad the gdm developers aren't slightly more moronic - with just a tad fewer brains they would be utterly unable to develop code that even they imagined should be released and we'd be spared all these "improvements".
P.S. Setting it back to "false" got things back to "normal".