analytics is great. It is free and gives some great stats for your site. It may not provide all the data that you require and you may want to consider other options. The nice thing though is that it is free and can try it out before optin for something else that might cost money.
I was using statcounter for a while...Until i descovered analytics...The interface could be a little better but it provides more stats that stacounter does...If you spend a little time and configure it you can learn exactly what keywords are converting.