Windows 8 has the metro UI, as well as a win7 like UI to use with mice, and keyboard.
Don't like the Metro UI, just run the regular windows-looking desktop
I'm afraid that's really not an option if you want to target all Windows 8 devices, as (I believe) many new Windows 8 devices would be Metro UI only. The Microsoft folks already use the word "legacy" with the desktop UI.
In other words, Microsoft means to say "please use Metro, but if you have legacy code don't be angry with us, 'cuz you have the desktop UI option... but not on all devices"
So the legacy mode will be available on both intel, and arm devices, which I believe will make up all windows 8 devices.
'Legacy' desktop applications would probably need to be recompiled to run on arm devices.
Windows 8 has the metro UI, as well as a win7 like UI to use with mice, and keyboard. Don't like the Metro UI, just run the regular windows-looking desktop