Equinox Desktop Environment
The Equinox Desktop Environment (EDE) is a DE designed to be simple, extremely light-weight and fast.
It primarily offers the most basic things: A window manager (PekWM is used), a simple GUI including a panel, a daemon watching removable media and a notification daemon. Other than that there's not much more than some configuration progams, screensaver, etc. Beginning with version 2.0, EDE follows the FreeDesktop.org guidelines.
Unlike any other desktop environment, EDE² is based upon the FLTK toolkit. It's especially fit for systems with little RAM or for users who want to customize their system and need a GUI that is not already bloated with functions and applications.
EDE is not very a very common piece of software. You usually have to compile it yourself (there are no pre-built packages for it). Fortunately on Arch there are two AUR-packages available that allow you build EDE it without much hassle.
The first one isAUR which is a dependency for EDE, the other one AUR the actual DE.
To bring up EDE you can either use a Display Manager or use startx. If you choose the later, just write the following to the .xinitrc of your user:
Since EDE is a bare-bone DE, you will have to add even the most common applications like a file manager or an editor yourself. It's all your freedom and choice.
Due to the nature of the DE, it obviously makes sense to install light-weight software. There are however not that many FLTK applications available so you will likely have to relay on a second toolkit like GTK+ for example.
File manager PCManFM
Terminal emulator Xterm