Google analytics and statcounter seem to be the most popular, what advantage does one have over the other ?
There are pros and cons to both really. I personally prefer analytics mainly because it is totally free. You have to pay for stat counter if want more log and pageloads. Currently my site hasn't been live that long to require more logs, so it's just wishful thinking. I also like the interface more for analytics and the graphs and goal tracking options are awesome. You could always just use both and see which one ends up suiting your needs.
I use histats.com to keep track of my traffic. Its pretty easy to use too. At first I wrote a simple php script to keep track of page views. Then I thought "why reinvent a wheel" and just used something that was already there.
w3counter.com here. I use analytics sometimes as well, but only to track some files to see how many downloads they have. w3counter is very good IMO
I just check the awstats in my cPanel. I don't like installing any additional scripts on my sites if not necessary.
I also use sitening for a few things. Not really statistics though. Just telling me if sites have good backlinks and some other things.
I've been using analytics for the basic info. It does a whole lot, although I've heard google uses those analytics to help consider ranks for your sites.
I am using awstats, just because they are already reinstalled on the servers! However, for larger sites, I like to use Analytics.