There are a few icons found in the Mac OS X’s System Preferences that I just never seem to use. Ever. They used to taunt me every time I launch Sys Prefs to make adjustments to my Mac – such as the MobileMe icon that still exists in Lion’s prefs, for example.
Why must the MobileMe icon taunt me? Oh. It doesn't!
You can hide any of those preference icons you want simply by visiting the View>Customize… while in the System Preferences. A small checkbox will appear next to each icon which you can untick to hide the icon. Once you turn off the icons you don’t use or for whatever reason wish to hide, simply hit the Done button at the top of the System Preferences window.