I use a combination of AWstats (supplied with cPanel or Plesk Parallel Panels) and google analytics. These combine give you basically all the statistics you need in nice graphs so you can see where you need to market. I also have the google analytics app on my android phone, and an app for cpanel so my site data is always at my hands and I can monitor it whenever! Super handy
I do use sitemeter (upgraded one) as an alternative for Google Analytics. It show the most comprehensive data of the site (metrics and all).