I've just installed both versions of Windows 7, 32-bit and 64-bit, through Parallels 8 on a Mac running Lion. Next step: installing Office 2010, Home & Student Edition. It works in 32-bit Windows 7, but I only tried this after it failed in 64-bit Windows 7, which is the OS I'd prefer to run.
In 64-bit Windows 7, the Office installation disk does not autorun (but it does in 32-bit Win). When I navigate to the setup.exe files (for 32-bit, 64-bit, and apparently 86-bit), clicking on them always results in the "Not a valid Win32 application" message and I can go no further. Clicking on the autorun file results in Notepad attempting to open the file for editing (FYI, Notepad fails because it says the file is too big).
I selected the same options for both Windows installations. What can I do to make 64-bit Windows 7 properly install Office? Why isn't it working?