Windows only: We’ve previously highlighted some disk space visualization tools with all kinds of neat graphics, but Treesize Free shoots for just the opposite—a clean, simple interface showing how much of your hard drive is filled by which folders. As you might guess, it stacks up the root folders by size, then lets you collapse them in nesting trees to see which sub-folders are eating up that 160GB drive you thought you’d never fill. You can adjust for KB/MB/GB viewing, scan CDs and removable drives, and switch to percentages instead of data bits, but one of Treesize’s really cool features is simply giving you all the same tools you have in Windows Explorer’s right-click menu on its tree view pane—delete, copy, cut, etc. Treesize Free is a free download for Windows systems only.