Example: my dad has a '97 Mercedes E420 that he paid $52k for in May of 1996, no financing, all up front. The car is almost 8 years with 96k miles on it. It still manages to look expensive and drive great so I don't see him getting rid of it for at least another couple of years and for that to happen it would have to be totaled in an accident or develop a major mechanical problem.

I would buy used if I was either looking for a project car or I was trying to find a particularly desirable car that has gone out of production such as the previous generation BMW 5-series as compared to the ugly new one. I would say though that I'm more inclined to buy a new car for something I would drive as my primary vehicle. I'm willing to spend more on the car initially because I will buy something that I plan on enjoying for a long time unless circumstances prevent otherwise. That's generally how I pick things to buy so I see no reason to go about it differently with a car.