Do you want to decorate your desktop but don't want to use compiz (or your system don't support it). With latest Gnome you can achieve this without affecting your system's performance. You don’t even need accelerated graphics to run Metacity with compositing. It even works well inside VirtualBox! If your computer can’t run Compiz, give this a try. Here are the steps...

1) Run Gnome configuration editor ( gconf-editor )
2) Navigate to Apps-->metacity-->general
3) Check the compositing_manager box, and Metacity will immediately restart with compositing!
4) Now you can install Screenlets, AWN etc. to decorate your desktop.