My name is Geoff, and I’m a Mintoholic.
Yes, it costs US$30 per site, but I think it’s worthwhile. It shows a lot of information in a small space and has a very usable Ajax-powered interface. It provides other ways to track your site stats (like an RSS feed of new referrers). Finally, it is extensible and many free plugins are available.
The only problem is that it makes you want to check it every 5 minutes, and get a third monitor!
Actually, there are a few other problems, but they are easily overcome.