I look at it like this: if the cost of repairing a used car over the years that you're going to have it is going to exceed the cost of a new car, obviously it's a bad bet. Hell, if it's even gonna be close, buy new if you can.
But if buying used isn't gonna cost you all that much in repairs, why not go for it? That way, you can buy a nicer car that's a little older. Personally, if I had the cash, I'd buy a 10 or 15 year old BMW that was in good shape and baby it. Those mid-nineties M3s... damn.
My mom sold off her turbo diesel Golf a while back because she was gonna retire, and that kind of car isn't meant for short trips. She bought a new Corolla to replace it. Here's the thing: I think she paid damn near 10Gs for the Corolla, after the trade in value.
It's a worse car than the Golf, by any measure. And how much would it cost to repair the turbo when it eventually got fucked up? A couple thousand, max.
So basically my mom paid more money for a worse car in my book. Buying new isn't always the way to go.