The Windows 7 taskbar automatically groups similar windows, and when you right-click on the grouped icon, you may get fancy stuff like a jump list or a task list, but you will also get a very small repertoire of window management options. In particular, the only option that operates on the group is Close all windows. What about the other group options?
To get a list of more group window options, hold the shift key when you right-click on the grouped icon. Then you'll get more options like Cascade and Minimize all windows.
Since the contents of the regular right-click pop-up window are dynamic, when you hit "C" for Close all windows, it still waits for you to confirm by hitting Enter. On the other hand, the shift+right-click menu auto-executes Close all windows when you hit the "C" hotkey. Doesn't save you any more keystrokes (trading an Enter for a shift key), but you do get predictability since the shift+right-click menu is pretty stable.
Bonus tip: To get the System menu for a window, you can right-click on its pop-up thumbnail.