Which version of Office Professional should I install? 32-bit or 64-bit?

Solution 1:

Microsoft's recommendation:

The 32-bit version of Office 2010 is the recommended option for most users, because it prevents potential compatibility issues with other 32-bit applications, specifically third-party add-ins that are available only for 32-bit operating systems.

That's the compatibility issue you raise in your question. The only real advantage to the 64-bit version is that you can work with more than 2GB of data (typically relevant to Excel). If you are working with truly enormous amounts of data and have run up against this limit (or have reason to think you soon will) then consider 64-bit. Otherwise I'd stick with 32-bit.