I am a big webalizer fan. I do have awstats and one other (I can’t remember the name) installed on my server however webalizer is by far the best and easiest to use IMO.
I have never used urchin, however I have been hearing a lot of good stuff about it. Now that google have bought it I am sure that we will be hearing a lot more about it. I am looking forward to using this in the future.