This is one of the more popular questions in the newsgroups. What tool do I use to analyze my log files? Here is a list that I seem to see posted all over. I didn't add all the commercial products, just the ones I've had a decent experience with. If you have experience with another tool, let us know. The more information posted, this will help those looking for this information.
Log parser - Free tool from Microsoft. This is my favorite command line tool!
AWStats - Free and open source tool that is popular.
Analog - Free
Smarterstats - free for one domain (written in .NET)
IIS Logging pack for SSRS 2000 - Add-on to SQL Server reporting services.
Urchin - Google product
Sawmill - has various builds
Webtrends - $$$ - powerful.