Those videos look more to be "concept" videos rather than actual Windows 7 footage. Right now Windows 7 looks pretty much like Vista. Most of the work going on is under the hood at the lower level.
While I can say I have never used Vista as a primary OS aside from playing with it, I can say if you get a computer with Vista, keep it. Don't go back to an older version if it comes on a new computer.
Microsoft as a corporation is having an identity crisis at this time. They're unsure as to whether they are a home OS company, a gaming company, a business company, a server company, or a web company. Sure there is always work going on with Vista/Windows 7 but there is other stuff going on as well. It's an identity crisis. All you need to do is take a look at Steve Ballmer (CEO). Another example is with the hostile takeover bid with Yahoo.
So there's a bit of internal confusion I'd say... Who does it come down on in the end? The end user. That's why Vista is what it is... sadly. All that said if you have Vista use it, don't go back to XP if it comes on your computer. If you are still on xp, give that a thought knowing that by Q1 next year Window 7 (codename) will probably be in beta.
Some food for thoought.
More Windows 7 info:
http://www.winsupersite.com/showcase/win7_shipping_02.asp
