The only real reason you might need to install Office 2007 on your Mac is if you need Microsoft Access, and don't want to go through Filemaker Pro for Windows to migrate Access to Filemaker Pro. Once in Filemaker Pro format, it can be put on Filemaker Pro for the Mac. Numerous applications for download and online offer free to nearly free access to Microsoft Word, Excel and Powerpoint documents, including LibreOffice, OpenOffice, Neo Office, Google Docs, and Zoho Docs. This would be much cheaper than installing a database on your Mac and PC, if Access is not part of the equation.