tracking disk usage on a Mac

When looking to track disk usage on a PC, I often use TreeSizeFree - which is awesome.  But I struggled to find something like that in a Mac.

I have used and like the trial of DaisyDisk.  It gives a graphical representation of all used files including hidden files and it can help you find things like Apple Mail usage or Outlook usage or itunes backups that can be eating up disk space within the Library folder.