SharePoint 2007 is ubiquitous now. It's eliminated most other document management and "collaboration" solutions in corporate settings.
Office 2007 Word, Excel and Powerpoint documents work pretty well in a managed Sharepoint document repository (library).
Oddly enough, other documents don't work nearly as well. They're very much second class citizens, with an unnecessarily clumsy and error-prone workflow for check-out, check-in, versioning and editing.
Funny how that works.
I thought Microsoft got in a wee bit of trouble for these sorts of games -- once upon a time. Too long ago, perhaps. Certainly nobody in the current US justice department is paying attention now.