I just saw a very interesting post from my friend Matt Paines on Google Analytics affecting ranking. I have actually been seeing sites loose rank over the past months with out any clear reason, all but one are using GA.
I am going to look into this again with the information Matt has posted on his site. For those who want to read more from Matt’s post got to http://blog.xseo.com/GoogleAnalyticsdamagerankings
There is also a interesting point made by Dixon Jones on this topic at the same post.