$5.00 a gallon, i.e. "the tipping point"

I wonder what will happen with the price of gas in the United States? I can't imagine that it will get too far above $5.00 a gallon. The current price ($4.19) hasn't quite completely shut the country down, it's just hamstrung us. I think that $5.00 would slow us down to about nothing.

From everything I've read, gas pricing has nothing to do with supply and demand, it has everything to do with speculation ....

How much is too much to pay?