I do like the idea of Windows 8 ARM (and Windows 8 and Windows 8 Phone and Windows 8 thingy-majiggy) though the names are getting a bit long.
Of course, what if they use the Windows RT on a non-ARM chip system? Then you may start breaking into Windows 8, Windows 8 AMD, Windows 8 ARM, etc.
They still haven't recovered from Metro, -er, I mean "Modern" interface name change! People don't know what to call it these days. At least, what to call it in public within ear shot of your grandmother!