is Woopra. If you don't manage a website then this is rather useless to you. but for those of you managing a website the things it offers in analytics are downright amazing. It tells you all the things that you can get with your regular stats. But it does so much more. The desktop client allows you to see currently who is on the site. You can tag particular users. (Although I have only tagged myself to know what percentage of visitors I am to my own site.) It shows you search terms, browser, OS, and screen resolution, it shows you the length of stay on the site and what pages were loaded. How many average sites were visited. Even more impressive, you can chat with visitors to your site while they are there. (A little popup appears on the page) I cannot think of anything I would want to know that it doesn't tell me.
In case i haven't been clear, Woopra rocks, use it on your site.