We are currently using sarg to analyse our squid proxy logs, while it works ok, its not really amazing and we could do with a bit more information. The main thing we would like to do is be able to give a manager a restricted view of what his staff have been up to, broken down by time (i.e. its ok to go on shopping sites at dinner, but not at 9:30am)
We dont mind paying if the software is good and well supported, but free is better!