Great post from the Broke Wino blog with some suggestion on finding good, cheap wine.  I think that his location suggestion is a great one.  There is definitely better value to be found in certain areas than others.  I have found 2007 Cotes du Rhone for $9, which for a good vintage of French wine is pretty good.  Certainly it's not Chateauneuf-du-Pape or anything, but it's a good wine for $9.  I agree that Argentina has given some great values, and would add that another to look at is Chile.