Please don't take my question the wrong way, as i am sure you have done research on this. Why would you want to buy a new car opposed to a "newly used" car?
Don't new cars drop in price the second you drive them off the lot?
-A new car has an OEM warranty.
-You can negotiate significant savings by playing dealers against each other so you have much more leverage than on craigslist.
-You suggested Hertz/Enterprise. Those are the last places you want to buy a car from!