Slingscold - Slingscold is a lightweight application launcher similar to Launchpad in Mac OS X.
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Listary - Listary is a revolutionary search utility for Windows
TreeSize - TreeSize tells you where precious disk space has gone to.
Scherlokk - Mac OS X application. Simple and user friendly, Scherlokk will find your media and missed files - quickly.
SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.