Mac: The dock is a handy tool for quickly accessing apps, folders, and files, but it isn't terribly well-organised. Tab Launcher offers a dock replacement that gives you multiple docks, categorised with labelled tabs.
Organizing your apps into various tabs is Tab Launcher's primary function, but it's also highly customisable. You can change an app's icon in just the tab, change the angle and intensity of its drop shadow, the label that shows when you hoever over it, the spacing of all the icons in any given tab, and a ton more. You can also add as many tabs as you want, and those tabs can consist of anything you choose or draw from dynamic information like running applications, recently modified files, or a real folder. If you want to get started with your current dock, Tab Launcher can import its contents to save you some time.
Overall, if the OS X dock is lacking a bit for you and you'd like a little more organisation and functionality, Tab Launcher is worth a look.
Tab Launcher ($0.99) [Mac App Store]