1)   SizeExplorer Pro 4.1
Powerful disk space usage analyzer with folder size, charts, statistics, duplicates finder, clickable reports, complete file listing, exports, printing, search, file management, loading and saving of explorations (snapshots) and compare of snapshot.
folder size, treesize, duplicates, compare, tree size, disk space, disk usage, disk analyzer, foldersize, folder sizes,

 2)   PMP 6.1
PMP is a performance monitor for remote Windows servers. You can monitor the real time CPU, memory and disk usage status from the several networked servers and can be notified for the specific server status.
performance monitor, CPU monitor, memory, CPU usage, memory usage, disk usage,

 3)   DU v 1.00 r 7
These 2 applications enable you to answer the question: "where has all my disk space gone?", and once answered, the disk space can be quickly and easily reclaimed. DiskUsage & DiskClean are distributed together as one utility package.
Disk Housekeeping, Disk Usage, DU Command, Disk Clean, Disk Usage Report, Disk Usage Analyser, Disk Usage Analyzer, Lost Disk Space, Automatic Space Recovery, Remove Temporary Files,

 4)   DiskAudit/2 1.1
DiskAudit/2 identifies the usage of disk space on a multi-user Windows PC. For each user, the program summarizes the total number of files and directories, hidden, system, and common files and folders.
Disk Audiit, Disk Usage, Disk Utilization, NTFS,

 5)   O&O DiskStat Professional Edition 1
O&O DiskStat is a high-power tool for analyzing the used disk space on your storage volumes. With an easy-to-use interface, you can take a closer look at the file and folder structure of your internal and external drives.
investigating space wastage on the hard disk, hard disk space, space, space wastage, hard disk usage, disk usage, disk stat, diskstat, 3d chart, treemap,