My 'personal bests' in speed and expense come from likely-sounding contenders (Ferrari, Bentley) and what might seem an unlikely interloper: BMW.

More and more of the fastest road cars are being artificially limited to a 'responsible' 250km/h (155mph). Given that there are very few roads in the world where you can legally use such high speeds, it's difficult to argue against the trend. But there are still a few unlimited cars.

Ferrari 575M Maranello: £160,000 supercar with a top speed in excess of 200mph.

At the SMMT Test Day in 2004 I drove a Ferrari 575M Maranello with a top speed of 202mph. The UK list price then was £163,200 (about US$284,000). It's an impressive piece of machinery: floor the throttle at 120mph in top gear and it pins you to your seat – it's like second gear at 40mph in a hot hatch.

An honorable mention must also go to the Bentley Continental Flying Spur Speed (£137,000 in 2009), which tops out at 200mph and accelerates at supercar-challenging rates despite its 2.5 tonne weight.

But neither rates as the most valuable car I've driven. That honour goes to the pre-war BMW 328 owned by John Muschamp, chairman of the BMW Historic Motor Club. The BMW, which I drove for a Classic Cars feature in 2009, is currently worth around £400,000.

John Muschamp's BMW 328: worth £400,000 (photo: BMW Historic Motor Club)

Second place in the value stakes goes to Ray Potter's SS Jaguar 100, which I drove the same day as the BMW and was worth £250,000.

Third place falls to a Bentley R-Type Continental which I drove in 2006. It was insured for £200,000.