See my blog at www.mindsharpblogs.com/daniel.
It also references Heather's questionnaire.

Team sites  are where we work and collaborate.
They present much more flexibility in
- security
- search crawls
- temporary work locations. (really stuck for a word here... don't want to use
areas, places, sites... all the good words are taken.)

The intention of the Team site  site definition configuration is
collaboration. It results in a Web that contains navigation and Web
Parts that facilitate its intended use.

The intention of all Area site definition configurations is organization
and presentation of Area Listings. They result in Areas that contain
navigation and Web Parts that facilitate its intended use.

While collaboration can be done within an Area, it is discouraged.
Unfortunately, sometimes people don't want to hear.

Another helpful argument or discussion point is permissions. I can often successfully discourage use of areas  where WSS sites  are better suited based on the limitations with list and library permissions within areas.