To accurately describe a wine I think that both varietal and geography play an important roll. But, I also think that geography is a much more difficult subject to grasp, as there are so many more geographic areas than grape varieties. Sure a Pinot Noir from Bugundy tastes quite different from an American Pinot, but they share some things in common. Same with a Cab from France, Austrailia and the US. They will all be significantly different but there will also be some underlying similarties. For the average person, I think that it is much more important to understand variety than geography. It will give you a reference point at which to start understanding wines, then you can start to learn how the geography of an area affects it.