Most of the linux users use either KDE or Gnome desktop environments. Apart from those two,there are many desktop environments available for your linux. LXDE is a definitely one to mention here. The “Lightweight X11 Desktop Environment” claims to be an extremely fast-performing and energy-saving desktop environment.It comes with an eye candy interface , keyboard shortcuts support and additional features like tabbed file browsing.It curbs very little of your CPU and RAM.It can be very effective when your system resources are limited especially in case of cloud computing.It can be easily installed and configured  in Ubuntu. If you are using Ubuntu 9.04 or above then you have LXDE repositories by default.

Installation

If you are using Ubuntu 9.04 or above then take the command line and type in

sudo aptitude install lxde

Screenshots