Much discussion is beginning to develop online as beta versions of the new version of Microsoft Office are getting tested. The new software introduces new default file formats that are not backward compatible with older versions of Office. You can save your files in the old version, but this requires an extra step and is a nightmare if you are trying to send a file to other people--it is impossible to know what version of Office everyone has.
No doubt part of the format change is due to Microsoft's shift to XML as the base architecture for data storage, but conveniently, the change will also force nearly everyone to buy a new copy of Office. It is one more reason to use PDF files as a standard document format when sharing files, but the PDF format does not solve this problem entirely if you want the receiver of a file to make editing changes to a document. And many Windows users have trouble creating PDF files (Macs will create a PDF of any file from any program without requiring additional software--it is built into the operating system).
It is no coincidence that services like Geek Squad and Geeks on Call are proliferating. Keeping a Windows computer running smoothly is a lot of work. With all new Macs able to run Windows natively side by side with the Mac OS, there are fewer and fewer reasons to have a Windows-only computer.