Last week’s average price for a gallon of regular unleaded was $2.26. That’s the lowest national average price so far this year. Prices this low make it seem like someone hit the reset button and Hurricane Katrina’s impact on fuel costs never happened. During the year after Katrina, and the resulting $3-plus gas prices, we in the car-news business didn’t go a day without hearing about small cars and fuel efficiency overtaking buyers’ mindsets. We’re not expecting a return to the SUV-filled days of the 1990s, but it’ll be interesting to see how these prices — if they stick around — impact sales of the flurry of new subcompacts entering the market.