GeekTool on the Mac AppStore
I never expected to see GeekTool make it to the Mac AppStore. As the name implies, it is really for serious nerds. It's an awesome tool and I use it on my MacPro to provide system info on the Desktop. Since menu bar and Dock space are a premium on a 13" screen, GeekTool spreads the info out across my Desktop and also provides some nice aesthetics as well.