Fluxbox
Fluxbox is a window manager for the X Window System based on Blackbox 0.61.1. Its goal is to be lightweight and highly customizable, with only minimal support for icons, graphics, and only basic styling capabilities for the interface. Keyboard shortcuts, tabs, and simple menus are used as interfaces, which can be edited. Some users prefer Fluxbox over other window managers due to its speed and simplicity.
The visual appearance of window decorations in Fluxbox is customizable by editing text files. Fluxbox themes are compatible with Blackbox themes which can be edited. Colors, gradients, borders, and other basic appearance attributes can be specified; Recent versions of Fluxbox support rounded corners and widgets.
iDesk, fbdesk or ROX Desktop can be used, in conjunction with Fluxbox, and for additional improvements gadgetry.
Fluxbox is the default window manager used in Damn Small Linux due to its low memory footprint and fast load time, Fluxbox is popular on many LiveCDs such as Knoppix STD and Gparted.