Microsoft's Office suite included numerous tools for generating visual information, including the drawing tools in Word, the charting options in Excel and the numerous layout settings in PowerPoint. However, those options aren't suitable for creating more complex diagrams, such as floor plans, engineering diagrams or organisational charts.

Visio fills that gap, providing an extensive range of diagramming tools for creating all sorts of professional visual output. Visio has long made use of an Office-style interface, a process that has only accelerated following Microsoft's acquisition of the original developer in 2000.

Visio is now sold as part of the Office family, but separately from the core package. For this review, we examined the Professional Version, which is somewhat pricier ($862 for new users or $433 for upgrades) but includes a much wider range of chart and diagram types, including engineering layouts, network rack diagrams, floor plan options, and extra options for IT professionals such as software engineers, database designers and network administrators. Many users will be just as satisfied with the Standard release, which excludes those extra diagramming options but still includes every type of visual most average users will want and is considerably cheaper ($348 for new users and $173 for upgrades).

Whatever type of diagram you want to create, Visio uses an easy-to-understand system of templates that come complete with all the options you're likely to require. The floor plan template, for instance, includes building elements such as walls, doors and cabling. These can be dragged onto the main plan, resized as required, and connected to other elements. Each element acts intelligently depending on its type (so if you move a wall, for instance, the associated door will also move). More advanced options allow you to associate executable scripts with diagram elements and export them online for use as (for instance) process maps.

As well as the copious volumes of templates in the main program, additional templates can be downloaded from the Office Online site. Well-designed tutorials take you through the main program elements, although basic diagram creation is intuitive enough to not really require this.

Files are saved in VSD format, but can also be exported in other formats (including JPG, TIF, AutoCAD and HTML). A free Visio viewer is available so you can share your creations with other users who don't have the main Visio viewer.

While the price is probably high enough to deter casual purchasers, Visio represents excellent value for money, and has matured into an essential tool for professionals who frequently find themselves needing to create diagrams.