if Microsoft Windows 8 or RT is backwards compatible and works with the billions and counting software that is available for the Windows 98/2000/XP/Vista/Win7 OS' families then I am all for it.
The reason Windows is great (subjective I know but i can't being to explain the hate I have for Apple's closed/restricted system and its unfair practices) is that its use is unlimited. You can find software for anything, you can tweak it (legally) as much as you want. There is so much integration with other software. There are so many free and greatly functional alternatives to paid software. You can connect it to many types of network inlcuding VPNs. Microsoft's own enterprise products work seamlessly with other software/services whether email (exchange), communicator (lync/ocs), sharepoint, etc
In the end if Microsoft can retain the software/services of the desktop os, they will be a big hit whether surface or not. If they can't, say hello to another windows phone 7.