WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
TreeSize - TreeSize tells you where precious disk space has gone to.
Scanner - This tool uses a sunburst chart to display the usage of your hard disk or other media.
DaisyDisk - DaisyDisk is a disk analyzer tool for OS X that visualizes hard disk usage and allows to free up hard disk space.
Rymotely - All-In-One Finance & Business Management designed to help Micro & Small Companies run and manage their business in one place.
WizTree - WizTree quickly finds the files and folders using the most space on your hard drive. It scans the MFT (Master File Table) instead of crawling the entire disk which makes it very fast.