I'm using Yandex.Metrica (http://metrica.yandex.com) and happy with it

These are open source:

http://piwik.org/

http://www.openwebanalytics.com/

Yes, Piwik I can highly recommend! The fact that you are doing the analytics by yourself also means they don‘t become part of a larger graph–in theory, this is better for the privacy of your users because you can’t track them outside your domain.