I've got
Statcounter on my blog, and it seems to work very well. After installing a small amount of code (invisibly if you like...that's how I've got mine set up) you get a detailed look at how many hits you have per day, how many are returning readers, and you can also look at a detailed list of each visitor, including what IP they are using, the link they clicked to reach your site, and what page they entered your site at.
The free version is just fine...the main limitation with it is that it only keeps the last 500 hits you've had in the log.