2012 Audi Q5 Hybrid
Perhaps this one should be filed under "tell me something I don't know," but Audi is king when it comes to all-wheel drive in the premium luxury segment. Audi sold 437,792 vehicles with all-wheel drive in 2010, with the Q5 taking the lead with 155,025 all-wheel drive models sold. Of the remaining cars Audi sold, roughly one quarter were equipped with all-wheel drive.
Of course for many, the real news isn't that Audi sits at the top when it comes to luxury-segment all-wheel drive sales. It's that Audi sells cars that aren't all-wheel drive in the first place. However, despite the brand's connection to the technology, not every vehicle comes with quattro all-wheel drive, although all of its vehicles are available with it.
Audi's association with all-wheel drive is 30 years old in 2011, and not surprisingly Audi isn't being shy about it. The company revolutionized the World Rally Championship in 1981 when it campaigned an all-wheel drive two-door hatchback known as the Quattro. Ever since then, Audi has been steadily refining its quattro all-wheel drive system to apportion power and torque to where it's needed, and attracted many followers in the meantime. As a side note, there's a certain amount of confusion about whether "quattro" is capitalized or not. The rally car that started it all is the Quattro, whereas the optional all-wheel drive system is quattro, with a lower-case "q."
It's debatable as to whether Audi still offers the best all-wheel drive system, but it's certainly the most ubiquitous in the luxury segment, and thus not surprising that it's the most popular around the world as well.