Mac OS X only: While the introduction of Stacks to Leopard was a welcome feature for some, others—particularly those who had grown accustom to navigating their filesystem through folders in the Dock—weren’t terribly pleased at the loss of folder navigation from the Dock. Freeware application HierarchicalDock restores hierarchical navigation to the Dock and throws in a handful of new and useful features (like Quick Look integration). To enable a hierarchical folder rather than a Stacks folder, just drag the folder to the HierarchicalDock app then drag it to the Dock. HierarchicalDock is freeware, Mac OS X only.