This is the simplest hit counter I could imagine (well, almost). Every time a 
page is requested, it adds one to the count. The display is not an image, just 
text. There is no javascript to hit some third-party server, no tracking, no 
distinction among pages: just an old-fashioned site counter CGI, implemented in 
WordPress. The plugin stores its count in its own MySQL table.
Once the plugin is installed (described below), you can display the count by 
putting code like this somewhere on your page:
<pre><code><?= simplehitcounter_hit(); ?>
</code></pre>
That will both increment the counter and display its value. There is no method 
for getting the value without incrementing it. I suppose I could write such a 
thing if anyone likes.
There is a minor race condition. First the plugin updates the database by one 
(atomically), then it queries for the current count. Therefore in heavy traffic 
it is possible for two updates to happen before either select. In that case, 
the counter will correctly increment, but the number displayed may be the same 
for each user, representing the total page hits. As far as I can tell, this 
race condition is inevitable without locking the table. It seems trivial 
enough, though I guess you should be warned if you run a contest to give away a 
free car to the 1,000,000th user.
By default the plugin keeps its data in a table called <code>wp_simplehitcounter_hits</code>. 
You can change this by editing the <code>simplehitcounter.php</code> file.

Simple Hit Counter

Prints a count of the number of hits your blog has received, tracked in the 
database.

StatCounter

The Official StatCounter WordPress Plugin brings you all the powerful StatCounter features to your wordpress blog.
Including but not limited to the following:
<ul>
<li><a href="http://statcounter.com/features/#invisible-counter" rel="nofollow ugc">Invisible Counter Option</a></li>
<li><a href="http://statcounter.com/features/#configurable-counter" rel="nofollow ugc">Configurable Counter</a></li>
<li><a href="http://statcounter.com/features/#configurable-summary-stats" rel="nofollow ugc">Configurable Summary Stats</a></li>
<li><a href="http://statcounter.com/features/#magnify-user" rel="nofollow ugc">Magnify User</a></li>
<li><a href="http://statcounter.com/features/#drill-down" rel="nofollow ugc">Drill Down</a></li>
<li><a href="http://statcounter.com/features/#popular-pages" rel="nofollow ugc">Popular Pages</a></li>
<li><a href="http://statcounter.com/features/#entry-pages" rel="nofollow ugc">Entry Pages</a></li>
<li><a href="http://statcounter.com/features/#exit-pages" rel="nofollow ugc">Exit Pages</a></li>
<li><a href="http://statcounter.com/features/#came-from" rel="nofollow ugc">Came From</a></li>
<li><a href="http://statcounter.com/features/#keyword-analysis" rel="nofollow ugc">Keyword Analysis</a></li>
<li><a href="http://statcounter.com/features/#recent-keyword-activity" rel="nofollow ugc">Recent Keyword Activity</a></li>
<li><a href="http://statcounter.com/features/#search-engine-wars" rel="nofollow ugc">Search Engine Wars</a></li>
<li><a href="http://statcounter.com/features/#visitor-paths" rel="nofollow ugc">Visitor Paths</a></li>
<li><a href="http://statcounter.com/features/#visit-length" rel="nofollow ugc">Visit Length</a></li>
<li><a href="http://statcounter.com/features/#returning-visits" rel="nofollow ugc">Returning Visits</a></li>
<li><a href="http://statcounter.com/features/#recent-pageload-activity" rel="nofollow ugc">Recent Pageload Activity</a></li>
<li><a href="http://statcounter.com/features/#recent-visitor-activity" rel="nofollow ugc">Recent Visitor Activity</a></li>
<li><a href="http://statcounter.com/features/#country-state-city-stats" rel="nofollow ugc">Country/State/City Stats</a></li>
<li><a href="http://statcounter.com/features/#visitor-map" rel="nofollow ugc">Recent Visitor Google Map</a></li>
<li><a href="http://statcounter.com/features/#isp-stats" rel="nofollow ugc">ISP Stats</a></li>
<li><a href="http://statcounter.com/features/#browser-stats" rel="nofollow ugc">Browser Stats</a></li>
<li><a href="http://statcounter.com/features/#os-stats" rel="nofollow ugc">O.S. Stats</a></li>
<li><a href="http://statcounter.com/features/#resolution-stats" rel="nofollow ugc">Resolution Stats</a></li>
<li><a href="http://statcounter.com/features/#javascript-stats" rel="nofollow ugc">JavaScript Stats</a></li>
<li><a href="http://statcounter.com/features/#email-reports" rel="nofollow ugc">Email Reports</a></li>
<li><a href="http://statcounter.com/features/#multiple-site-management" rel="nofollow ugc">Multiple Site Management</a></li>
<li><a href="http://statcounter.com/features/#user-access-management" rel="nofollow ugc">User Access Management</a></li>
<li><a href="http://statcounter.com/features/#public-stats" rel="nofollow ugc">Public Stats</a></li>
<li><a href="http://statcounter.com/features/#blocking-cookie" rel="nofollow ugc">Blocking Cookie</a></li>
</ul>

StatCounter – Free Real Time Visitor Stats

StatCounter.com powered real-time detailed stats about the visitors to your blog.

Simple Hit Counter vs StatCounter – Free Real Time Visitor Stats