Booting Debian without X/GDM

Simply remove the startup links for the display manager. e.g I used gdm3 :

sudo update-rc.d -f gdm3 remove

Reboot and voila, my little Thinkpad is running as an exim4 MTA, mysql rdbms, apache virtual hosting server and general lan gateway but with an extra few hundred megs of RAM as we haven't loaded the extremely heavy X........