Sounds like you're looking more for tracking stats - if so, there's a great thread here listing some recommended options:
http://www.threadwatch.org/node/5850
I've used a basic version of webtrends myself and it was pretty excellent - I could see where someone came in from, what pages they visited, how long for, and when they left.
The problem I had with the software is that - at least at the time - usage was charged on a pageview basis, and I really wanted to use it on forums - and they traditionally generate a *lot* of pageviews.