For the third year in a row, Porsche was the top-scoring brand in the nation's best-known measurement of new-car quality, the J.D. Power and Associates initial quality survey.

The survey asked 81,500 buyers more than 200 questions about possible design or production problems they've encountered with their new cars and trucks.

Porsche buyers reported 87 problems per 100 cars, well below the average of 118 problems per 100 vehicles and down from its 2007 score of 91 problems per 100 cars.

Infiniti displaced Lexus for second place with an average of 98 problems per vehicle (and rising well past its 2007 rank of ninth).

Lexus took third place with an average of 99 problems per 100 cars. Mercedes-Benz and Toyota tied for fourth place with an average of 104 problems per 100 cars.

Honda was the only brand with three models receiving top marks within their segments -- the subcompact Fit, compact Civic and CR-V crossover.

Jeep was the worst-performing brand, with 167 problems per 100 vehicles. Other brands in the bottom five were MINI, Land Rover, Saturn and Suzuki.

If you're in the market, check out our recommendations on the best new cars and trucks for 2008.