I have used a software called Piwik quite some time now to keep track of statistics for the pages that I built in Drupal. Piwik is another fantastic example of how the open source community is working very well!

Lots of people spend lots of time to build things that You and I can use for free. If that does not make Your heart warm then I don´t know what does ^. ^

Here is the site: http://piwik.org/

It´s very easy to install and You will find great documentation on the site as well.