For the best economy, go for a 1.9 TDI diesel, which has an official average of 55.6mpg in standard form, and 62.8 in BlueMotion trim.
However, the 1.6 FSI petrols can return more than 40mpg and, because used petrol Golfs are cheaper than diesels, they can make financial sense if you do a below-average annual mileage.
The high-performance Golfs should make your heart race when driving, but the insurance, fuel and maintenance bills might do the same while stationary.
The 1.6 FSI S 3dr starts at 6250 for an '05-plate car with 45k miles, and up to 8800 for an '07-plate 5dr with 16k miles. An early '05-plate 1.9 TDI S 5dr can cost just 5000, but it will have covered up to 100,000 miles.
An '07-plate 2.0 TDI GT 5dr in GT spec with 25k miles should be less than 11,000.