If you are in the process of deciding whether to deploy Office 2010 32-bit or 64-bit, I recommend to read through the following content. Note that Microsoft recommends installing Office 32 Bit even on Windows 7 64 bit.
TechNet – 64-bit editions of Office 2010
Understanding 64-Bit Office
Compatibility Between the 32-bit and 64-bit Versions of Office 2010
64-bit Client Installation of Microsoft Office 2010
Office Resource Kit Blog – Office 2010 64-bit editions
4SysOps – Office 2010 – 64-bit vs. 32-bit – Part 1: Installation
Microsoft Office 2010 Technology Guarantee: FAQ