I recently watched this video about checking your search engine ranking which explains that you might not be listed as high as you think you are because Google personalises the results and lists websites that you visit regularly higher than ones that you've not visited before.

http://www.bradleyspencer.com/2009/does-yo...than-you-think/

I don't think that is quite right though. From my understanding Google only does that if you are using the Web History on your Google account. Does anybody else have any experience of this?