Doughnuts...mmm. Pie...mmm. Which one would you pick? No, it's not a dilemma to share with Homer Simpson! These are two of the chart styles available in Microsoft Excel 2007. And the rest of the categories are just as appetising. But when do you choose a doughnut instead of a pie?

In Microsoft Office Excel 2007, you can use new charting tools to easily create professional-looking charts that communicate information effectively. Based on the theme that is applied to your workbook, the new, up-to-date look for charts includes special effects, such as 3-D, transparency, and soft shadows.

Now that you have learned how to create charts, there is an extensive array of styles that can be applied to your spreadsheet data in order to produce a professional chart. Microsoft Office Excel 2007 supports many types of charts to help you display data in ways that are meaningful to your audience. When you need to create a new chart, or change the type of an existing chart, there is a wide range of pre-stored chart types which you can select from.

A chart has many elements. Some of these elements are displayed by default, others can be added as needed. You can change the display of the chart elements by moving them to other locations in the chart, resizing them, or by changing the format. You can also remove chart elements that you do not want to display.

But the main factor which influence the decision regarding charts is the data which needs to be displayed.

If you want to display data changes which have been made over a period of time, or to compare data over different time periods, column charts are ideal. Usually categories are displayed along the horizontal axis and values along the vertical axis. There are also numerous subcategories of styles which can be applied to column charts including clustered column, stacked column and 3-D column.

Another style of chart which is ideal when showing trends over a period of time is a line chart. line charts with markers are another excellent way of representing the order of data.

Even the old favourite Bar chart can be refreshed with a cluster bar or stacked bars treatment.

If you need to show a large change over time, an area chart can be used to highlight the total value across a trend. For example, profit over time can be plotted in an area chart to emphasise the total profit.

For the optimum order of data on a worksheet use a scatter chart. Put the x values in one row or column, and then enter the corresponding y values in the adjacent rows or columns. Scatter charts are best used when dealing with scientific and statistical data.

Stock charts are perfect for representing data that fluctuates - such as in the stock market. It is important to input and organise data in the pattern you want to present results. For example, peaks and troughs should be presented in columns of peaks and troughs.

A surface chart can be applied if you need to compare optimum combinations between different sets of data. Just like a topographic map, colours and patterns indicate areas that are in the same range of values. Surface charts can look extremely interesting in wireframe or contour shapes.

Bubble charts add an interesting graphic to any presentational chart - again it is important to collate data in a certain order before applying to a bubble chart. This chart facilitates the understanding of social, economical and scientific data relationships. Another way to display multivariate data is in a radar chart, and this is a comprehensive method to compare values and relationships when using several data sources.

Obviously if none of the chart types is suited to the data you want to display, you can create your own bespoke charts in Microsoft Office Excel 2007. Gantt charts and floating column charts, for example, can easily be simulated by using a bar chart or column to replicate a floating column chart.

If you need to highlight different types of information in a chart, then by combining two or more chart types might make the diagram easier to understand.

And the choice doesn't stop there. There are many more styles you can create, or even use SmartArt to design your own style.

In answer to the original question, a doughnut chart displays data in rings and could be utilised when the relationship of individual data as a percentage of the entire data is required, and when there is more than one data series to highlight. If there is only one data source to be highlighted, then results would definitely be demonstratable in a pie chart. Options include showing results as pie of pie, and exploded pie in 3-D to name only two.

If this has whetted your appetite, then get yourself a piece of the pie and find out about a professionally run training course on Microsoft Office Excel 2007.