Charts and graphs can be powerful ways to convey information to the reader. OpenOffice.org Calc offers a variety of different chart and graph formats for your data.
Calc allows you to customize charts and graphs to a considerable extent. Many of these options enable you to present your information in the best and clearest manner. For readers who are interested in effective ways to present information graphically, an excellent introduction to the topic is Cleveland, W. S. (1985), The elements of graphing data, Wadsworth Advanced Books and Software.