Google Analytics for WordPress
The Google Analytics for WordPress plugin automatically tracks and segments all outbound links from within posts, comment author links, links within comments, blogroll links and downloads.
StatPress
The first real-time plugin dedicated to the management of statistics about blog visits. It collects information about visitors, spiders, search keywords, feeds, browsers etc.
Adsense Stats
Adsense Stats is a widget for WordPress to display detailed statistics about your Google Adsense earnings without requiring login into your Google account.