I always use a raw log file analyzer like Brad said, usually AWstats which is pretty standard but I know there are more full featured ones out there now.
If you’d rather not install a script on your webhost you can use something like http://www.StatCounter.com which gives you an invisible piece of javascript that you put on every one of your pages, and it’ll automatically track the stats for you in a web-based interface. It’s free up to a few hundred thousand hits per month.