Buying used is the way to go in my opinion. The second you drive that new car off the lot you've just set thousands upon thousands of dollars on fire.
Also, it's a bit of a crapshoot whether new cars actually give you the peace of mind. Co-worker of mine just had his truck (that he bought new) explode on the highway a few weeks after his warranty was all up.
The end result was a bill for over $10,000.
Crap happens with vehicles no matter what the age of them, and the average vehicle is never going to be an investment.
Save up the cash, buy it outright, and you'll be financially ahead of most others.