[xp84]

Love this! A few similar GUI apps have been mentioned for Windows. For Mac, I've been using GrandPerspective for probably 15 years. This is one of my favorite class of programs in terms of how uniquely useful they are.

A pity we can't use something like this (and actually take action on the results) on closed systems like iOS (I've just had to factory reset my iphone to rein in a 37GB "system data" mess... even on the newly restored phone that consumes 15GB but at least that's better).