Boot Ubuntu desktop in terminal mode

# vi /etc/default/grub 
....
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash text"
....


# sudo update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-3.5.0-18-generic
Found initrd image: /boot/initrd.img-3.5.0-18-generic
Found linux image: /boot/vmlinuz-3.2.0-32-generic-pae
Found initrd image: /boot/initrd.img-3.2.0-32-generic-pae
Found memtest86+ image: /boot/memtest86+.bin
done

# sudo reboot now


To start desktop:
# startx