I;m new here- I did an intro, so I hope it's ok to participate without seeming like I am barging in.
Amy D is a huge used car proponent, but her dh once did buy a new car, but it was some sort of crazy deal. I think she wrote once about buying new only if you could pay cash. I think...well, let me get the book, lol, so I know what I am saying...ok here it is:
"Purchasing a new car can only be considered economical if you plan to own it for more than 10 years, you maintain it meticulously, and you buy it with cash. The exception would be if your cash is invested in a safe plan that has a higher interest rate than the interest rate you could get for a car loan. At least try to pay off the loan quickly". (She also mentions not buying a compact car if you are planning a family etc).
This was before 0% car loans, obviously. If a person can pay 30k cash or so for a car without it denting the budget or sacrificing more important things, then who are any of us to say what a person should spend their money on, yk?
I've has such great luck with used cars. We;ve not owned very many cars and I like not having monthly car payments, even if they were to be 0% interest. I'm currently driving an 8 yr old Volvo wagon that I love. It's got everything and I paid 3k for it. Can't beat that with a stick. It was a 35k car new, yk? Even if I have to fix something in the next few years (did a ton of research before I bought it and had it checked out etc), it's still nowhere near a monthly car payment on a 30K loan. And given that so many new cars have issues and recalls, it's hard to say that even a new car won't present with some problems. They'd be covered, but you would still have the aggravation.
While buying new is an option, so is buying used. The right used car at the right price is going to be an easier pill to swallow than $400-500 montly payments for years. Unless money isn't an issue and you have the 30-40k available. If ya do, that's *cool* and you should buy what makes sense for your family. Well you should do that anyway.

But if I had 40k readily avilable, I'd take the kids on a trip around the world.