Filelight has also been doing this in KDE since about 2003. I still think it's slightly easier to use than DaisyDisk, since the labels actually point to the sun

Filelight has also been doing this in KDE since about 2003. I still think it's slightly easier to use than DaisyDisk, since the labels actually point to the sunburst chart. But DaisyDisk does look much spiffier.