Gramps - Research, organize and share your family tree with Gramps genealogy software.
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Ancestry - Discover your family history and start your family tree.
TreeSize - TreeSize tells you where precious disk space has gone to.
MyHeritage - MyHeritage is a family-oriented social network service and genealogy website.
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.