Diesel enthusiasts can rejoice: after a year of significantly higher prices, the average cost of a gallon of diesel fuel has fallen back below the price of premium gasoline, according to Autoblog.

Diesel now averages $2.18 per gallon, compared with $2.19 for premium gas and $1.96 for regular. Now that we're finally beginning to see some clean diesel vehicles that match gasoline cars for clean emissions and beat them on EPA fuel economy estimates, the falling cost of diesel fuel could help spur sales of cars like the 2009 Volkswagen Jetta TDI, the BMW 335d, and the various Mercedes BlueTEC models.

I've driven both the 335d and the Jetta TDI recently. Both cars are solid options for environmentally-minded enthusiasts, and have a much greater cruising range than their gasoline-powered counterparts. The 335d is also ridiculously quick; Car and Driver clocked its 0-60 time at 5.7 seconds, and the 425 lb-ft of torque makes it feel even faster from behind the wheel.