Here's a review of the Windows 7 taskbar:
http://i.gizmodo.com/5131933/giz-explains-why-the-windows-7-taskbar-beats-mac-os-xs-dock
Turning the taskbar into an full blown app launcher does ring of similarities (I do think they took some 'inspiration' from OS X) however I see it as more of a combination of the previous quick launch feature, and of Vistas taskbar preview feature.
The Dock on its own might not be as useful as the new taskbar, however when you combine the features of both the Dock and Expose (which is a far more appropriate comparison since the new taskbar attempts to combine the feature of both), OS X's functionality tops it, in my view.
Here's why:
- Expose works the same way regardless of the amount of windows you have, while Aero Peek breaks down once you reach the limit of the screen width.
- While Aero Peek gives you full size previews of your windows, a full size preview is not totally necessary if you just need to identify a specific window.
- Expose allows you to view all windows, or just the windows from one app. The new taskbar does not allow you to see all windows at the same time, while what it does allow you to do is still a slower process compared to Expose, requiring you to move the mouse down to the bottom of the screen, hover over the app icon, then hover over each windows preview individually, then choose. Contrast with Expose where you press a button or move to a hot corner (you do not need to specifically aim for a icon), you see the windows all together (rather than individually), then you click to choose.
It's certainly a great improvement, however combining the distinct functionality of an app launcher and window management into one feature has its limits. OS X's distinct implementation of these functions is overall more successful.