Good program to visualize file system usage on Mac? [closed]

"Have a look at

Daisy Disk

With DaisyDisk you can free up disk
space by quickly finding and deleting
big, useless files. The program scans
any mounted disk and displays it on
the sunburst map, where segments mean
files and folders, proportionally to
their sizes. The map is easy to read
and navigate. You can also quickly
preview any file and reveal it in
Finder to delete.

OmniDiskSweeper is also another alternative.

OmniDiskSweeper presents you with a
list of disks attached to your
machine. Double-click on one, and a
new window opens with a “column” view
listing every folder and file you can
access, which it sorts by size as you
watch.

You then simply browse through the
folders and files and delete the large
ones which you are no longer using. If
a file is part of the system, it'll
say so on the panel (in the list of
Packages the file belongs to), so you
won't accidentally get rid of
something that would make your system
stop working. The free space on the
disk and the ordering of the folders
are automatically recalculated.

OmniDiskSweeper is freeware."

GrandPerspective is an Open Source app that will do what you're asking.