A very simple way to disable Google Analytics when you don’t want your visit to be registered (for instance when you’re working on your CSS or making a page with a template that embed the GA tracker) : just add a variable to load the tracker (or not) depending on the context :

Here’s my version :

<script type="text/javascript">
  var testmode=false;
  if(/taiste.acadis.org/.test(window.location.host)
      || /.*admin.*/.test(window.location.pathname)
      || /.*noga.*/.test(window.location.search)
      || /.*noga.*/.test(window.location.hash))
    testmode=true;


  if(!testmode){
    var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
    document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
   }
</script>
<script type="text/javascript">
 if(!testmode){
   try {
     var pageTracker = _gat._getTracker("...");
      ageTracker._trackPageview();
   } catch(err) {}
  }
</script>

Here, GA won’t be loaded for urls like example.com#noga, test.example.com and so on…