From my experience it's not just about documenting the objects, but how they're accessed and their purpose; and ensuring that the documentation is up to date.  MS Word, as the author suggests, requires someone to keep it up to date; and we all know how well that turns out.  There are many tools out there, all with their good points, but I personally wouldn't ever consider one which didn't offer me the ability to run as part of a build, or nightly task.

On the subject of tools; my shameless plug is for DBDocumentor from Pikauba Software (http://www.pikauba.com/DBDoc/details.htm).  It works from the SQL sources so it won't be for everyone, but the tradeoff is that you can get information about result sets and data accesses/modifications.  It also has support for SSRS RDL, so that's a good bonus.

Cheers