I love and loathe stats.

I love them because you can see how well your website is doing. I hate them because it can often be difficult to see how your website is doing, because constructing meaning from data can be tedious.

For those looking for free stats software, here’s a few packages that do a pretty good job of conveying meaning. If you’re a free stats software vendor, or if you know of other stats packages, please feel free to add them to the comments.

• Google Analytics – This used to be called Urchin, and it used to cost money. No longer. Google bought Urchin, and made the software free. Very comprehensive, often overwhelmingly so. Thankfully, there are a lot of great tutorials and user groups.
•  HitTail - HitTail will be of particular interest if you’re into SEO. The software reveals in real-time the least utilized, most promising keywords hidden in the Long Tail of your natural search results.
• StatCounter – basic stats, but sometimes, simple can be good. Used by a surprisingly high number of sites, probably due to it’s ease of setup and use.

Wikipedia also has a list of server based stats software.