(http://www.complete-seo-training.com/images/google_heat_map.jpg)
Big shock, most in the top left corner, occasionally on the right side if it's a separate column.
(quote from the sales-pitch-page)
Here is a "Google Heat Map" image created when doing research tracking users' eye and mouse movements to find what most web surfers look at and click on when doing a search. It works a bit like a weather map, with areas with the most activity appearing in the brightest colors.
You can see the top 4-5 organic results get the most attention. Lower on the page, most users don't bother to read the page titles all the way across to the right side. The results at the bottom of the page get very little attention. The sponsored results (Adsense ads) on the right side get much less attention. Most web surfers have learned that the results at the organic results at the top of the page deserve to be there for a reason, and that is where they are most likely to click.
Reminds me of a AJAX script that tracks click locations of your users and displays a heat map over lay of where they click.