I have been using the free version, which is the ultimate version includes all of the great features, such as video, support for more than 2 monitors on a laptop (depending on the hardware) and many other features.
If you want to give it a try, and the resources required are much less than the Vista requirements, for instance I have been using it on an eee PC Netbook with 1 gigabyte of RAM, and it works GREAT!
Installation is almost instant if you follow the instructions at:
http://blogs.technet.com/coolfactor/archive/2009/06/05/installing-win7-using-a-usb-drive.aspx
(But do this type of install only if you want to start with a "clean" build, that is everything is wiped off of the drive.)
The free Windows 7 is at:
http://windows.microsoft.com/en-US/windows7/products/home?os=win7
If you want to buy it for half price directly from Microsoft, you can get it at the Microsoft Company store for a limited time:
http://www.microsoft.com/windows/buy/offers/pre-order.aspx



