According to an economist on the financial news today, the price of any given grade of gas may rise another $1.20 this year before leveling off or decreasing. The economist based this on both Goldman-Sachs and T. Boone Pickens' speculation of oil reaching $150 per barrel this year. The math works like this:
On average, a gallon of gasoline increases 3 to 6 cents per every dollar increase of a barrel of oil. Oil closed today (5/20) at a round figure of $130. If it is forecast to increase to $150 sometime this year, then you take the $20 difference and multiply it by the worst case scenario of 6 cents. The result: $1.20. Tack that onto today's price, and there will be your high for the year.
Enjoy it now, because in a few years, oil should be over $300 a barrel, making it near prohibitive for civilian use.