Check this guy out:

Update: He pulled the video.

He claims the Windows 7 Taskbar is copied from the Mac OS X dock. He even includes an edited image featuring the same Adobe icons he has in his dock to try and make it seem even more similar. Apart from that he also makes numerous mistakes and wrong assumptions about how the new Taskbar works, and does the standard everyone is copying Apple line, which is completely and utterly false yet it something the Apple fanboys repeat ad nauseum.

Here's a little time line for graphical user interface (Hat tip to ToastyTech for the screenshots).

Xerox PARC create the Alto - the first computer to use a mouse and a graphical user interface (no Taskbar yet).

Apple employees visit Xerox PARC to check out the Alto, after seeing the Alto they begin work on a graphical user interface for their Lisa computer (no Taskbar yet).

Xerox introduce the Star, featuring overlapping windows, double-clicking and dialog boxes (still no Taskbar).
Microsoft begin work on Interface Manager, later to be renamed Windows (still no Taskbar).

Visi Corp releases Visi On, the first GUI for IBM PCs (no Taskbar).
Microsoft introduce Windows (no Taskbar).
Apple release Lisa (still no Taskbar).

Apple introduce the Macintosh (still no Taskbar)

Geos released for Commodore 64 (no Taskbar)
Amiga Workbench announced (still no Taskbar)
Microsoft release Windows 1.01. The first operating system to have something resembling the Taskbar, an area of the screen reserved for iconized programs. See below:

Windows 1.01

Apple release the Macintosh II, featuring colour graphics at last, if I was a fanboy I'd say they copied colour graphics from Windows, but I'm not (no Taskbar though).

Acorn Computers release Arthur (the forerunner to RISC OS). Featuring something resembling the Taskbar, its been so long since I've used RISC OS I've forgotten the name for it.

Microsoft release Windows 95, creating the Taskbar we all know today, featuring a Start button to start new applications, and a tray for running applications to sit in.

Windows 95

Microsoft release Windows 98, which allows shortcuts to programs to be placed in the Taskbar (called Quick Launch).

Windows 98

Apple release Mac OS 9, which features a slide out "dock" along the bottom of the screen.

Mac OS 9

So no I don't accept that Microsoft copied the Taskbar/dock whatever you want to call it from OS X.

He could of quite easily shown the Taskbar with text labels, and without the Adobe icons which were edited into the picture he used.

Windows 7

Or the new Taskbar configured to look like the existing one:

He also claims because the Taskbar items also have menus that they've also been copied from the dock. Newsflash: The Taskbar items have always had menus which have always been customisable by the applications running, now there is additional APIs to plug more information into the Taskbar.

But of course if this guy told you the truth he wouldn't have an argument would he?