A couple of new window management features of Windows 7 are quite remarkable. First of all the shake of windows, that hides all other screen clutter. Shake the window again and the other windows come back. This is an excellent, fun, and easy to remember gesture to remove distractions and focus on the current task. For me on Mac the shortcut Cmd-Opt-H has a similar effect. It hides all windows from other applications. But I suppose it is not as much fun, and not consistently implemented across all applications. Back to Windows' gesture, I would expect just one caveat: The trigger MouseDown-RapidSmallMouseMovements works best with a mouse -- a trackpad is not the best graphical input device to perform this gesture.
Two other gestures grabbed my attentions. Move a window against the upper border of the screen and it maximizes. Move it to the right or left border to use the right or left half of the screen. These gestures simplify the task to compare two documents side by side. A small, yet powerful aspect to work with windows.
There is another shake gesture that becomes fashion. Shake Apple iPods and you get a new random song. I would like to see this feature for iTunes as well. Shake the iTunes window to randomize to the next tune. Alt-Click on the forward button is my most used function in iTunes anyway.