WebLog Expert Rocks!
I have been using WebLog Expert Pro for many years to analyse the large log files from The Probert Encyclopaedia (they are roughly 100mB a day in size). I continue to be delighted with the analysis results which are easily available from WebLog Expert. Previously I used Analog, but there is just no comparison. Updates continue to be free, and the company appears to be in touch with its customers. I can not praise and recommend them enough.