A supply of gasoline sufficient to last for years will be a very large problem. Gas deteriorates and becomes unusable within a couple of years, although there are additives that can extend its life for a year or so. Available stockpiles must be rotated, using oldest first. Diesel, on the other hand, will last up to about 8 years, and can be supplemented with filtered vegetable oil. Also, the supply of diesel fuel will be larger, as most folks don't use it. Those that have diesel-powered vehicles will be in luck.
At any rate, mobility, power, food and self-protection will be the keys. Unfortunately, deciding WHAT the emergency will be in advance is next to impossible, except for one I'm predicting right now. The country is going bankrupt with out-of-control federal spending, and an economic collapse is highly probable unless something is done at the ballot box in 2010 and 2012.
The power grid is easily disrupted by weather or terrorist action. Those of you who live in the colder climes in the winter will be in big trouble for heat. For those of us who live in a warmer environment, it may be as simple as putting on a jacket and/or an extra blanket at night.
Living in a remote rural area with trees, a water supply and game in a mild climate would be ideal for about any scenario, including CBR warfare where the big cities are the most likely to be hit.
And you will find that you can't go it alone. A good-size group of people is much better able to cope and defend than one or two people. A group can have specialties, such as medical, dental, logistical, an armorer, hunting, power, perimeter defense, etc. Each member of a group should be able to contribute a specialty and be cross-trained in other specialties, a la Special Forces personnel. That's what survival will be all about.
As to any other scenario besides monetary collapse,