GNOME comes with a useful utility which does that as well called Disk Usage Analyser. Usually installed by default via the gnome package on many distros.
With a binary name of `baobab`. I always wondered, what the mnemonic here was/is.
Other alternatives:
• du | xdu
• filelight
ncdu when you don't have x
Thanks for letting me know about this, what a handy utility.
I even prefer ncdu even if I have X. It's just that good.