Comment 12 for bug 454420

If someone wants to "tweak" gdm look and feel, it could be done running the line below as root:

# sudo -u gdm dbus-launch gnome-appearance-properties

Xubuntu 9.10 GDM theme is fine for me (if Ubuntu users are annoyed by the Human Theme, they could give a try on Kubuntu or even Xubuntu). IMHO, Human Theme hurts my eyes, I stick with blueish tones in [K|X]ubuntu.

There is another way, but it might mess up GDM: downgrade it to the older version (I didn't try and I wouldn't try, even knowing how to 'pin' packages to avoid updates). It's a kind of surgical procedure and I don't recommend it to someone who relies on front-ends to configure such trivial stuff (sorry if I has been a show-off, but it's true).

Like anything on Linux, you always can seek another path. I would try it in /etc/gdm/custom.conf where it's possible to change themes (at [greeter] section) easily. All custom settings done in this file won't be superseded by any upgrade, so your beloved theme won't be touched if it's compatible with your GDM version.

HTH