DiskFerret analyzes your disks or folders and display several (very nice) graphs, including pie, radio, treemap, etc as well as biggest file lists.
It also can delete or ZIP files, and has a duplicate file finder.
A search function with filters for names, size, etc is also available.
Unfortunately, my experience with it while reviewing wasn't very good. The first time I ran it after installing, it gave me an error message about Java not Found and closed.
Luckily, it ran the second time. Time to analyse a 100GB is reasonable (about 7 min).
However, I had a bad problem – when switching between some of the functions the program would give me message boxes with each of the folder names! Needless to say, in any large drive this required going to Task Manager and forcing the program to close. Must be a logging function that the programmer forgot in, but it does make sections of the program unusable.