2012 BMW 3-series. Long the benchmark car in its sector, Richard Hammond thinks the latest 320d could well be best car ever built. And he may be right. It's not particularly cheap, but top speed is 146mph and 0-62mph takes 7.7sec. Then there’s the fuel economy. It has a combined fuel economy of 61.4mpg, which works out at an amazing 52 mpg in real world driving.