Windows 8 is due to launch on 26 October in several different flavours, each offering something different.
Confusingly, there is a tablet-only version, in the form of Windows RT, and then multiple forms of Windows 8, which is tablet and desktop compatible. So which Windows 8 is for you?
The standard version of Windows hasn't yet been priced in the UK by Microsoft. It is almost identical to Windows 8 Pro, bar a few minor differences, but you can't add on Windows Media Centre to the standard version of Windows 8. So those who have all-in-one PCs with TV tuners might want to go for the Pro to get the most out of their machines.
You do get Windows Media Player, plus access to both Metro or Modern-style apps and core Windows applications. This standard version of Windows 8 also has all the other design and looks tweaks you would expect to find in Windows 8, including a new task manager and the disappearance of the Start menu. Prepare for a little confusion.
Windows 8 Pro
Windows 8 Pro is the operating system to which Microsoft wants you to upgrade. For Windows 7, Windows XP and Windows Vista users, an upgrade costs £24.99. You will of course be able to buy a Windows 8 Pro version separately if you are installing it clean on a new computer.
For all intents and purposes, this is the complete Windows 8 experience. It gives you everything Microsoft has put together for the new operating system, including the Modern UI look that you get in Windows RT.
This version of Windows comes with the facility to add on Windows Media Centre, Microsoft's computer-based media management software. The Media Centre can sync with a TV tuner and lets you record and watch live TV. It can also be used to manage and play back music and movies.
Other than that, Windows 8 Pro doesn't add much over the standard edition that's of use to the average computer user, other than the ability to boot from a VHD and join a Windows domain.
You can install Metro-style apps to Windows 8 Pro from outside the Windows Store, but quite how that process will manifest itself and whether it will be something important to do remains unclear for now. We certainly wouldn't lose any sleep over it.
Windows 8 Enterprise
Windows 8 Enterprise is the sort of bumper business edition of Windows 8. It offers everything the new operating system can handle, except for being able to add Windows Media Centre, which is available on with Windows 8 Pro.
While a lot of what Enterprise adds is very complex, all should be useful to big businesses. Enterprise, for example, has a client and host-based version of remote desktop. There is also advance data encryption software, like AppLocker.
Read: Windows 8 review
Windows To Go and DirectAccess complete the functionality of this very business-minded version of Windows 8 but it's probably also very useful for developers for the Windows 8 platform too.
Windows RT is, in essence, a scaled-down version of the full Windows 8 experience sized to fit on a tablet. For Metro apps and the touch-based live tile interface of the new Windows, it's perfect.
Where Windows RT becomes limited is in its ability to run x86 apps. This kind of application is found on conventional Windows desktop machines.
Instead Windows RT is restricted to apps downloaded from the Windows Store. At the moment this means core Windows apps such as Office and Excel, as well as a few of the heavy hitters such as Netflix, but that's about it. For everything else, it's the Metro/Modern UI versions only.
Read: What is Windows RT?
Don't let the inclusion of a desktop confuse you, Windows RT is much more restricted than Windows 8 in capabilities. It is an operating system built for tablets and should give you a much more iPad-like touch orientated experience.
Which one is for me?
If you are after a tablet and nothing else, then Windows RT should be your weapon of choice. Running on ARM hardware and built specifically for tablets, the software is less battery hogging and should mean your tablet lasts longer.
Then come all the versions of Windows 8. Simply put, if you are upgrading, Windows 8 Pro gives you everything an average computer user would need for the reduced price of £24.99. Then again it might be that Windows 8 minus the Pro appears in upgrade form later and even cheaper, so perhaps wait and see.
The Windows 8 Pro upgrade is also available as a disc from places such as Amazon, priced in at £50. Here's a trick though - download it and you get the ability to make a back-up disc or USB for free, so you can save yourself £25.
If you aren't upgrading, then Windows 8 alone should suffice and is likely to cost less than Windows 8 Pro.
Otherwise, Windows 8 Enterprise is clearly put together for business. Unless you are in an office, it's unlikely the extra cost will be justified.