SpaceSniffer is a freeware disk space analyzer for Windows that make use of the Treemap concept to view the current disk usage. Among the most notable features you'll find:

Features

• drag and drop support
• intuitive structure layout (multiple views for different media)
• zoom elements (browser-like navigation)
• powerful filtering (you can filter your results based on size file name age)
• customizable options (geometry, colors, behavior)
• fast scan of your hard drive (navigation worked even when the scan didn't finish)
• support for NTFS Alternate Data Streams and so on.

SpaceSniffer is fully portable on all modern Microsoft Windows versions (doesn't have a setup file. Therefore it doesn't mess up with your current registry - it just adds an XML configuration file). You can use the executable file on other Microsoft Windows OS; there's no need to extract the archive each time.

SpaceSniffer Screen Shot

SpaceSniffer Home Page

Download SpaceSniffer

SpaceSniffer Portable Version