The Mac iWork suite includes vital features from the typical office suite:

• Word Processor. The Pages '09 program does a good job of not only Word Processing, but letting you open documents from Word with minimal conversion errors.
• Spreadsheet: The Numbers '09 program includes all of the standard spread sheet and graph functions, and also does a great job of working with Excel spreadsheets.
• Slideshow presentations: Keynote '09 fits that awkward roll filled by many presentation programs of glorified bulleted list word processor. In this genre it performs well, but like most programs of this sort is relatively uninspired. Unless you consider a multitude of screen fade ins to be riveting for your audience.