The answer to this question depends on the finances of the borrower and condition of the car. A 72-month term has been the norm in recent times, but some loans have terms that are longer and some have terms that are shorter. While the prospect of stretching a loan out for the lowest monthly payment may seem attractive, you should keep in mind that the longer the term is, the higher the interest rate is, and therefore the more you will pay for your car in total.
Also, keep in mind that cars do break down, and they are more likely to break down the older they get. No one wants to be making monthly payments on a broken car. In the end, deciding on an appropriate car loan term length comes down to what your current monthly budget will allow, but the shortest term you can afford would be the best option.