I have driven them all other than the S14.
Assuming we are talking about handling on a basic street setup not a full blown track car.
From them I think the best overall handling from a street perspective is the S15 aswell. While possibly the S13 might actually handle better on a track from being a bit lighter, I find that the S15 feels more solid/less clunky/smoother and gives a better overall feal which is important on a stret driven car. The steering also seems to feel a bit quicker than in the Skylines (not sure, might not be but feels like it).
However the best handling overall Nissan I have driven is a 370Z. Now just gotta get some one to give me the keys to a R35
EDIT: Also since it is kind of part of the family and should be mentioned. The 300ZX was the worst handling Nissan import I have driven. The steering is horrible in it and requires huge amounts of lock to turn.