Review:

SpaceSniffer remains our Editors' Choice for three simple reasons, first and foremost it's free and second it seems to be far and away the best free space disk analyzer, and thirdly it is standalone (i.e. no install). It only took about a minute to do the whole drive.

It can display free space and unknown space. The program reported the space as: Free 160.1 GB, Used 119.1 GB. The "levels of detail" is button selected (8 levels). The "Go home" button takes you back to master display. You can drill down by double clicking on an area.

The default colours are: drive (orange), free space (green), folders (skin tone), unknown space (gray) and file (blue). All are changeable. Can change contrast, border contrast and a hi-light halo level (when a file is selected or mouse is hovered). There is an export function that will give you either the file list in the selected directory or stats about that directory: this did not seem too useful.