Microsoft finally allowed retailers to take your pre-orders for Windows 8 Pro and various other editions
Important: The OEM edition is currently only available in selected regions
Amazon usually has the best pre-order guarantees:
Windows 8 Pro – The Best Version?
Many users are usually confused when Microsoft releases a new Windows version. Why? Because there are so many different editions and not all of them are equal. Some allow you only to upgrade from previous versions, while others are stand-alone editions or ship without the Media Player
Windows 8 OEM Standalone – Apparently Only On Selected Retailers
Actually, it’s quite easy. If you are not buying a tablet or computer with Windows 8 you should buy an upgrade edition and use it to upgrade from one of the previous versions (XP,Vista,7). A standalone OEM edition does not seem to be available from many retailers. The OEM version (standalone) is currently available on the German Amazon website, but appears to be absent from Amazon.co.uk and Amazon.com as of right now
The regular editions lacks a couple features and the Pro edition has a few more features than the RT edition. To compare all features download our free PDF