If you spend a lot of time creating and manually formatting new tables in Excel, there's a better way. Simply select the range of cells that you want to include in your table and click the Format as Table button:
You'll be prompted to confirm your cell range:
And then you can go in and customize the headers (just click in the cells and type) and begin entering your data and formulas:
If you want to customize, select New Table Style and make your own:
This feature works in both Excel 2007 and Excel 2010.