The cost of gas obviously affects the price of everything else.
Its also an indicator. Lower gas prices mean more income for the average consumer, and it reduces the cost of shipping for everything.
Its also an indicator that the economy is slowing down. So while I love cheap gas, I also recognize that its telling me something. If you sell cars, or blue jeans at the mall, or your factory sells transformers, your business is probably also falling off. Less stuff being shipped means less pressure on the price of fuel.
Consumption of gasoline is up, not down.