OK, Audi and Peugeot diesels did dominate the Le Mans 24hr results - though that really is down to the gas/diesel equivalence rules. In World Touring Cars, they get diesels and petrol winning different races, mainly because they are constantly fiddling with the rules to keep the two equal.
However the point of this post is more mundane - The Times (sorry, that'll be The London Times for you guys) did nice back-to-back test of a BMW 520d and a Toyota Prius between London and Geneva, adding in 100 mile of city driving to give the Prius a decent chance:
Toyota Prius proves a gas guzzler in a race with the BMW 520d
Don't have a heart attack when watching/reading this - they are talking in UK gallons, that are 20% bigger than US gallons, so their 48mpg(UK) is only 40mpg(US).
Andrew