Be mentally prepared to get a myriad of responses. 
For me, paying in full will always beat paying by instalments.
Quite common sensical actually.
But that will never happen on me, so if I have around $30k, I
will look out for a new car that costs not more than $60,000. I
will use that $30,000 as downpayment, pay the rest under
instalments for no more than 5 years.
I am quite skeptical about used car actually. Maintenance and
stuff can be a chore. Furthermore, there are still a
range of new cars to choose from, within the $60,000 range and
below, currently.
It all depends on your financial situation.
Just my 2 cent's worth though.... 
