I saw this article today and I think it is a good one for all of us to read, as it addresses many of the things we are talking about in this thread

http://www.survivalblog.com/2010/01/coa_analysis_of_common_surviva.html

The author changed my perception on a few things. The range you can actually expect out of your vehicle during a societal meltdown and the number of looters/raiders that one would be faced with in the cities being the ones that gave me the most to think about.