The Name Game
With lots of concern over a possible burgeoning range of Windows 8 versions, Microsoft has set minds at rest by naming just three core versions, plus an Enterprise edition. They are Windows 8 and Windows 8 Pro for Intel architecture devices and Windows RT for anything running ARM, which will be a sizeable number of tablets first and perhaps low-power PCs later.
Any version of Windows 8 will allow users to use a touch screen or keyboard and mouse, and switch between them at will. With a Windows app store bringing all the latest Microsoft and third-party software to the desktop, Microsoft finally has a modern architecture to compete with Apple's iPad and Google's Android army. The ARM version can't run x86 software so will be depending on a massive amount of apps in the store to stand a chance of succeeding.
Ticking the Boxes
The MS blog post, by Brandon LeBlanc, has a long feature-list table with some key differences and makes no mention at all of Metro (trying to get away from the codename?). For a start only Windows 8 or Windows 8 Pro will allow for upgrading from Windows 7. All versions of Windows RT will come installed on new hardware only. Windows RT is the only one that will come with the MS Office Suite (Windows 8 users will probably already have it, or look to upgrade to Office and Sharepoint 2013), but it lacks Windows Media Player.
Note, no mention of Metro in the post
Windows 8 Pro is the business version, being the only one sporting BitLocket, Boot from VHD, client Hyper-V, group policies and remote desktop hosting among other features. There will be an Enterprise version with all the features of Windows 8 Pro plus features for massive IT organizations that enable PC management and deployment, advanced security, virtualization, new mobility scenarios, and much more.
There does seem to be some confusion over the Windows RT name for ARM processors, like what does it stand for, and isn't there already a WinRT (Windows RunTime)? Microsoft needs to clear that up quickly and also answer why that version doesn't have a Media Player, or rather what will replace it?