I recently started using Ubuntu and I really liked the way things work in Ubuntu. I really like that when you setup Ubuntu Server distribution it does not come with GUI at all and that way it saves us from spending few mega-bytes of memory and we won't be wasting around 200MB behind graphical display and related processes, which we won't be using on the Server OS which usually does it's job without requiring us to install any GUI application on the Server.
But well many a time we may want to setup light weight x-window system on our Linux (Ubuntu) system and we can do that with setting up Xface or it's Ubuntu name as "Xubuntu".
To setup lightweight Xface or Xubuntu system on your Ubuntu Server setup you just need to follow some simple commands and that's it, you are done.
So if you are ready to setup, just follow some simple apt-get commands and install minimal packages required to setup lightweight GUI system on your Ubuntu Server:
# To get and install xfce4
$ sudo apt-get install xfce4
# Set of required packages for minimal setup
$ sudo aptitude install catfish elementary-icon-theme exo-utils flex gigolo gnome-icon-theme-full gnome-system-tools gnome-time-admin gthumb gthumb-data gtk2-engines-pixbuf indicator-application-gtk2 indicator-messages-gtk2 leafpad libclutter-1.0-0 libclutter-1.0-common libclutter-gtk-1.0-0 libcogl-common libcogl5 libconfig-inifiles-perl libencode-locale-perl libexo-1-0 libexo-common libfile-listing-perl libfont-afm-perl libgarcon-1-0 libgarcon-common libgdome2-0 libgdome2-cpp-smart0c2a libgegl-0.0-0 libglade2-0 libgnomevfs2-extra libgsf-1-114 libgsf-1-common libgstreamer-perl libgtk2-notify-perl libgtk2-trayicon-perl libhtml-form-perl libhtml-format-perl libhtml-parser-perl libhtml-tagset-perl libhtml-tree-perl libhttp-cookies-perl libhttp-daemon-perl libhttp-date-perl libhttp-message-perl libhttp-negotiate-perl libid3tag0 libido-0.1-0 libilmbase6 libio-socket-ssl-perl libjpeg-progs libkeybinder0 liblink-grammar4 libloudmouth1-0 liblwp-mediatypes-perl liblwp-protocol-https-perl libmad0 libmailtools-perl libnet-dbus-perl libnet-http-perl libnet-ssleay-perl liboobs-1-5 libopenexr6 libotr2 libots0 libsexy2 libthunarx-2-0 libtie-ixhash-perl libtimedate-perl libtumbler-1-0 liburi-perl libwww-perl libwww-robotrules-perl libxfce4ui-1-0 libxfce4util-bin libxfce4util-common libxfce4util4 libxfcegui4-4 libxfconf-0-2 libxml-parser-perl libxml-twig-perl libxml-xpath-perl libxss1 link-grammar-dictionaries-en m4 orage python-configobj python-glade2 ristretto synaptic system-tools-backends tango-icon-theme tango-icon-theme-common thunar thunar-archive-plugin thunar-data thunar-media-tags-plugin thunar-volman ttf-droid ttf-lyx tumbler tumbler-common xfce-keyboard-shortcuts xfce4-appfinder xfce4-cpugraph-plugin xfce4-fsguard-plugin xfce4-indicator-plugin xfce4-mount-plugin xfce4-netload-plugin xfce4-notes xfce4-notes-plugin xfce4-notifyd xfce4-panel xfce4-places-plugin xfce4-power-manager xfce4-power-manager-data xfce4-quicklauncher-plugin xfce4-session xfce4-settings xfce4-systemload-plugin xfce4-taskmanager xfce4-terminal xfce4-utils xfce4-verve-plugin xfce4-volumed xfconf xfdesktop4 xfdesktop4-data xfwm4 xfwm4-themes xubuntu-artwork xubuntu-default-settings xubuntu-icon-theme xubuntu-wallpapers gnome-system-monitor
# You may want to install firefox
$ sudo apt-get install abrowser
# Remove screen-saver, as you do not want to waste cpu-cycles on your Server-OS
$ sudo apt-get remove xscreensaver xscreensaver-data
Once you are done with above setup, you will be having working Xfce / Xubuntu on top of your Ubuntu Server. You just need to reboot and you will see decent Xubuntu log-in screen. You might think that why do I need to install Xfce4 and then all packages manually? but the reason is we are installing here only bare-minimum things instead of installing all packages which come with Xubuntu. So above setup installs visual themes, some packages which help you to view files, directories, configure system / network etc.
If you want to install complete Xubuntu on top of your Ubuntu-Server you just need to type, one line:
$ sudo apt-get install xubuntu-desktop
but, this way you will end up installing all those packages including office, multimedia and many others which you may not want on your Server unless you're going to use this system as development machine.