Formatting is an important part of a complete spreadsheet and not something that is done just to make it look good.
The choice of background color, font style and font size, plus other formatting options can make the important data stand out from the rest of your spreadsheet.
If you would rather not do all the work yourself, though, there are 17 AutoFormat styles available in Excel 2007 that will give your spreadsheets a professional look, and will make it easier for users to find the important information you are presenting.
The short tutorial on the Excel 2007 AutoFormat covers where to find these AutoFormat styles and how to apply them.
Other Formatting Tutorials