GaMerZ has quite a few plugins/hacks/mods for WordPress version 1.5. I’m currently using WordPress 1.5 Stats and you can see it in action here. The stats mod is not a plugin but a stand alone script that you drop into your WordPress root. I wanted the script linked from my list of pages so I created a blank Page and then altered my .htaccess file to redirect the newly created Page of http://www.bloggingpro.com/bloggingpro-stats/ to http://www.bloggingpro.com/wp-stats.php which is the stats script. There may be an easier way to do it but this is all I could think of.
WordPress 1.5 Stats does not display visitor stats but rather your WordPress statistics.