Selecting the right operating system when you buy a new laptop or PC has never been more important. With various versions of Vista available, you don’t want to get lumbered with an OS that gives you limited functionality and omits some of the key features you thought you were getting.

According to a recent PC Advisor survey, 73 percent of PC and laptop users were not informed by sales staff when they bought their systems that different flavours of Windows were available to them, and many buyers don't think to ask about higher-end versions of Microsoft's OS before making their buying decision.

Furthermore, our survey found that 51.6 percent of respondents use the same laptop or desktop PC for work and pleasure. Those people may need the high-end security features offered by the Bitlocker technology available with Vista Enterprise - the Windows version designed for large corporations that's only available via Software Assurance - just as much as the entertainment features available in Home Premium, but omitted from the business versions of Vista.

What's included in Vista Ultimate?

Microsoft argues that as Vista Ultimate is the all-singing, all-dancing version of Windows - offering users everything that's available in the consumer versions and everything included in Vista Business - it suits those who want to use their machine for both business tasks and home entertainment.

In addition to the business networking features, centralised management tools and advanced system backup apps included in Vista's Business versions, Vista Ultimate is the only Microsoft operating system to feature Windows Ultimate Extras.

These add-ons are designed to extend certain aspects of your operating system. Several are already available – including Windows DreamScene, Windows Hold'em poker, language packs for Windows, Secure Online Key Backup and the BitLocker Drive Preparation Tool - and more are on the way.

Read more about Windows Vista Ultimate Extras.

See the table below for a comparison of the major features of the various versions of Vista.