Microsoft Office 2010 (word processing & spreadsheets)
The standard business productivity suite, Microsoft Office is something everyone involved with any kind of business simply must have. Documents, spreadsheets, presentations and email. Some people say OpenOffice is just as good, but that simply isn’t true. While it’s close it lacks complete compatibility with the Microsoft proprietary formats. If you need to be able to share documents with people who use Microsoft Office then you need MS Office.
After all, Microsoft Office apps are really good at what they do. Excel spreadsheets and Word documents are powerful, easy to create and can look really good if you know how to do some layout. They print very well and integrate with Windows.