As X-Windows has grown along with the Linux operating system, many improvements and adaptations have been added. Window managers are part of the graphical interface. There is a variety of x managers out there. The window managers that you use, should really be based on what your using it for. IceWM is extremely resource friendly and yet is still useful.
E is well known for being one of the most graphical window managers out there.
Work on E has been executing for some time now, and as more time passes, more managers will become more dependable. A great part of Window Managers, are themes. Themes help control how the window manages look. Click here for an example of a theme. Say you want your system to look just like a Mac system.