How to install GUI in Ubuntu Server
You can install the default Ubuntu desktop by executing the following:
sudo apt-get install ubuntu-desktop
There are many desktop alternatives which you may install and use, like:
Gnome 3 installation: sudo apt-get install gnome-shell
XFCE installation: sudo apt-get install xfce4
LXDE installation: sudo apt-get install lxde
KDE see Kubuntu installation: sudo apt-get install kubuntu-desktop
Openbox installation: sudo apt-get install openbox
Another good GUI : sudo apt-get install gnome-session-fallback
