Sorry I felt the need to downvote this, but it's not necessarily a perl related question. That being said, I'll answer anyway ;)

I recommend that you look at either Analog or Webalizer. Analog is blazingly fast and handles gargantuan log files in almost no time. Webalizer, I thought, was easier to work with, and if someone who isn't a techie is looking at the results, Webalizer is definitely nicer.

Hope this helps!
MrCromeDome