I've had a number of cars and been privileged to drive a lot of other peoples cars.  Ones much faster than the 64 GTO, but when a neighbor kid got one I got to drive it.  In all the years since I still feel it was the most fun to drive.  It was maybe a low 14 second machine, but it went very smoothly through the gears and handled nicely.

Second place was a 69 Z28 Camaro.

Neither of these were real fast, but both were fun to drive and very street able.