Tired of the way the default windows shell looks?
Then try heading over to
http://www.bb4win.org/ - a port of blackbox for windows. It's a sort of minimalistic window manager, with pretty modest resource consumption (~10meg working set size, ~6meg private bytes on my machine). It's got skinning support, and is pretty snappy.
It's highly configurable if you don't mind getting your hands a bit dirty, supports multiple virtual desktops, has various plugins for various tasks, support overriding default windows keybindings (like Win+R -> FARR), and should generally just be tried.
You can simply download the zip (I got the bbLean release which is pretty barebone, Xoblite is supposedly more pre-configured), unpack, and run the blackbox exe - no need to replace your default shell right away. You can exit blackbox at any time, and get back to the regular explorer interface.
http://www.xoblite.net has a whole bunch of addtional plugins...
Here's a screenshot of my left monitor (I've got two TFTs) running blackbox with a few apps open. The black bar to the bottom left is "uberbox", a fancier version of the windows "Run" box with aliases and history completion - I'll replace this with FARR soon.