My most visited URL (March 2011) is about Japanese numbers 1 10. It has very little information and is very focussed. When you search in Google for Japanese numbers 1 10, without the quotes, almost all the information from the URL appears in the snippet on the Google Search Results page. I think this causes a lot of people to click on my URL and go to my site. This in turn causes Google to keep the URL high on the SERPs.
This shows that what appears on the Google Search Results is very important. If people tend to click on a site in the SERPS, the site will rise in the SERPS. If people find what they are looking for in the SERPS, they will click through to the site.
This only works where the information is very focussed and can be presented in very little content.
This page has a high CTR and an average SERP position of 3. All variations of the keyword phrase Japanese numbers 1 10 causes the page to be listed high in the SERPs. Good CTR seems to override many other factors: you dont even need a META description tag; you can have very little content on the page; you dont have to worry about getting links; all the other normal factors. But the big caveat is that it is very difficult to have a page with a consistently high CTR.