Gnome Shell by default only have always present top panel to make more room for your working windows. But by doing so, almost every information shown in top panel, thus making it cluttered and crowded.

These following Gnome Shell extensions will make your top panel more spacious and less cluttered. Tried and works in Ubuntu 12.04.

• Activities Button Text
  this extension enables you to rename the long and quite useless "Activities" text on your upper left screen to anything you like. 
  After installing this extension go to installed extension page to configure it, there you can rename it as you like. For demonstration I rename mine to "apn".
• Status only icon
  another almost useless text in top panel is "your name" in upper right screen, unless of course you tend to forget your own name. This extension will eliminate the name but retain the status icon.
• Quit Button and IM Menu
  Your computer state is not your social network state, this extension will separate these two into two icons : social network icon and power icon.
• Remove Accessibility
  if you don't need the Accessibility feature then lose it with this extension

Shown below my top panel with these four extensions installed (and one extension to show the desktop) click for larger resolution if you like. 

There you go, four extensions to make your top panel clean and spacious.



keyword : gnome shell extension declutter clean spacious top panel