I like Window Maker because its incredibly lightweight, easy to use, and it eliminates almost all the baggage brought by the Windows notion of a desktop (not that Windows' interface is bad).
Window Maker is dead simple...it's up there with twm (though more elegant than twm). No start menu, no task bar, no tray...nothing. Just right click for menu. Minimizing iconifies the window...the icon can be placed anywhere. Window Maker introduces very useful features not present in the classic Windows interface, like shading and hiding. Shading allows you to pull a window up or down like a window shade. So, if you have a maximized window with tons of other windows behind it, you can shade it to switch between the two without having to take the time to minimize/maximize. Window Maker also represent a process by an icon. The process icon is used to hold hidden windows or offers a convenient way to kill a process that may have many windows open. Hiding a window (a right click to iconify button) places all the windows of a process in the process icon. The process icon represents each and every instance of the process and its windows (e.g. Say you have 5 xterms open, hiding one of them hides all 5 of them). A click to the process icon restores all the process' windows as they were. The process icon can also be used to bring-to-front every single window of the process which is very convenient, especially with terminals and IM windows. Window Maker also introduces the notion of a dock which is similar to the tray in Windows. The difference is, the dock can be used to hold application shortcuts or dock applications. A dock application is usually an application that performs simple tasks like monitoring (e.g. weather, battery, clock, etc...). There are many other niceties of Window Maker besides what was mentioned, but these are the features that make it so incredibly mindless, effortless and simple to use.
Mixing this interface with a Unix-style mouse makes it even better...hover to focus is really nice since it removes a needless click.
Some other niceties:
- Minimize and kill are separate (left and right corner) instead of next to each other...so if you intend to minimize a window, there's no way you can accidentally kill the window.
- Window Maker offers seamless work spaces (i.e. drag windows to other work spaces, create workspaces on the fly without effort, etc...)
- GUI configurator...usually lightweight window managers rely on config files (e.g. fluxbox)...the GUI configurator offers convenient configuration of Window Maker without config files.
- Window Maker understands GNUstep, KDE, and Gnome semantics.
So its definitely worth a try if you want something new. It is less effort to use than the classic Windows interface in my experience (again, not to say Windows' interface is bad).