Blackbox is a quite easy to configure (once you're into it) shell replacement for Windows. It uses less system resources than the default Windows shell and is highly customizable.
It doesn't use an icon- based desktop like Windows, but you can access all your files and folders via self made short-cuts provided by a variety of plug-ins.
This is how my desktop look like now:

Most of the shortcut bars are hidden until I move the mouse over them and I can add and remove new control bars with little effort.
You can easily switch between the default windows shell and Blackbox, and it also doesn't change any critical system settings.
If you're an experienced user who likes to have total control over his desktop, Blackbox is well worth a try.
http://bb4win.sourceforge.net/bblean/