Analyse your website traffic:
In my experience, the best counter I used was WEBCOUNTER.BE. With this free and invisible counter, you cannot only view visits and hits. It also keeps statistics on referers (who links to your site) and searchengine hits (so you can see how your site performs in searchengines like Google or Yahoo, and the keywords used to find your website).
My advice: www.webcounter.be
It's free and easy! You can create a free account here.
Looking for a complete list of hit counters?
For a list of free and professional web counters click here