DiskBoss - A file manager with a focus on storage side of things: Monitoring, classing, storage, duplicate...
DiskWave - DiskWave is a free utility to help you determine where most of your hard drive space is consumed.
DiskSavvy - DiskSavvy is a free, fast and easy-to-use disk space analyzer utility allowing one to analyze disk...
RidNacs - RidNacs is a very fast disk space usage analyzer for Microsoft Windows.
Duc - Duc is a collection of tools for inspecting and visualizing disk usage.
Landiskape - Landiskape is a storage visualizer which tells you how your storage is being used by using an easy to understand 2D chart.