From CA to ID across to MI and all down to the the Florida keys and back across the south the best card I've found for all those areas and fuel up anywhere is a Master Card.
From what I've found there is no one gas charge card that will work in all parts of the country anywhere you need to refuel at a particular time. I'm always amazed at all the different brand gazz stations in different areas away from home.
Around my home area I use a Quick Trip cc for gas. For diesel around home I use the MC at places like Caseys (others) that sells lots of diesel fuel per month.
