GoAccess is an open source real-time web log analyzer and interactive viewer that runs in a terminal in *nix systems or through your browser. It provides fast and valuable HTTP statistics for system administrators that require a visual server report on the fly.
AWStats is a free powerful and featureful tool that generates advanced web, streaming, ftp or mail server statistics, graphically. This log analyzer works as a CGI or from command line and shows you all possible information your log contains, in few graphical web pages.
Advanced Web Stats uses a hybrid method to track your website visitors. You can parse web-server log files, add Java-Script page tags to your website or use both methods at the same time. This gives you a much better accuracy and also allows you to get real actionable data.