5 Great GUI Apps for Visual Disk Usage in Linux, Ubuntu [With Bonus]
Filelight, a GUI-based KDE app, provides a sunburst representation of disk usage. Instead of showing a tree view & list view of directories/files, it shows the usage in a concentric pie chart view representing each directory.
You can mouse over to a specific colour/pie to get the information about that specific segment. It also provides a way to dive deep into a particular segment to a single file level to analyze! This feature is pretty neat.