The difference between Windows 8, Windows 8 Pro and Windows RT - With only two versions of Windows 8 to be available to consumers, plus one for ARM devices (pre-installed only), what you get ought to be straightforward.
But, as is usual with a new version of Windows, there's still room for confusion because what you get with each version overlaps slightly.
Windows 8 (yes, just Windows 8) is the home version for x86 Intel and AMD PCs. The features you do and don't get mostly make sense; joining a domain, encrypting your disk with BitLocker and being able to log into your PC remotely are business features.
You can connect to a PC at work from a Windows 8 system, with Remote Desktop or a VPN, you can combine multiple hard drives into one storage 'pool' that has multiple copies of your files and you can mount VHD and ISO images as if they were hard drives – but you can't boot from a VHD file.
And anyone who speaks more than one language or travels between countries will be delighted that you can switch not just the keyboard but the Windows interface from one language to another without paying extra.