Clicky: http://getclicky.com/ (This is a good one)
Woopra: http://woopra.com/
Clicky: http://getclicky.com/ (This is a good one)
Woopra: http://woopra.com/
My one gripe with them is they seem to do more processing of the data, rather than just letting you find the numbers you need. I am a data hound, so YMMV
We have plenty of users who use both Clicky and GA together though. Clicky does "most" of what people need and they like the real time aspect, but when they really need to dig deep into complex analysis, that's when they hit up GA.
edit: stupid me i spaced out. it's a 500k daily pageview limit not monthly. doh! this should work.
I use three analytic and all of the them are free. I don't use woopra anymore, but I will probably use them if I am looking for a commercial solution. Clicky seems to have more customized tracking solution and looks like a better solution for people who are looking for a more in-depth tracking data.
Sitemeter.
Wordpress SiteStats.
The only one I frequently check for basic, quick, stats check is Sitemeter. If I want to go in to details I will check the other two every few weeks.