If you ask me, it's not a huge rip-off of Mac OS X.
First, Look at the start menu. Note they got rid of start and put in the windows logo. Seems just like mac.
It also reminds me of KDE and Gnome, although the approach they took is some-what unique, as the button extends larger than everything else on the bar.
Also, those screenshots from the video seem to be from a fake video of Vista using something like WindowBlinds. I'm thinking this as the search bar is absent from the start menu, explorer looks different, and i've never seen that trayish thing on any screenshots of Vista i've seen. The start menu button looks different than it should too, even with Aero disabled.
If they want to prove it's Vista, perhaps they should show the fancy new
Task Scheduler in another video.
I would just like to remind people here as well that Microsoft Windows had built-in ZIP compression (ME/XP) before it made it into Mac OS X, and supported built-in file encryption via XP (Pro Ed.) before it as well. I know I might be making some fanboys angry mentioning this sort of thing, but I don't care. I've had nasty experiences with Apple trolls (I didn't say every Apple user is a troll, to any trolls that may be reading this). Someone makes a claim that Apple brought widgets to the desktop, and I bother to mention they were on Windows already via third-party software (e.g. StarDock), and it's like i've started some sort of holy war with them. Just tired of the "Apple innovates before everyone else" attitude of certian individuals. Apologies for the semi off-topic rant.
I will admit i've noticed that Windows has some features Mac OS X had before it, but would also like to mention Linux has beat Windows to implementing features as well. Yes, that's obvious, I know. I bring it up though, because it supports my original comment, that Vista isn't just a big rip-off of Mac OS X. Microsoft doesn't get their ideas from a single source.