Wish I could vote on more than one. I drove a 280zx (s130) in high school so that would be my top choice. But a buddy had a 300zx (z32) in college and man was that a honey magnet. These are my top 2.
At heart I love all Z’s but the S30 is a cornerstone of automotive design so it takes it by a landslide. You can plug that bitch into any time period and it fits no matter what. Yoshihiko Matsuo was a genius.
I agree with you that the current-gen Z (RZ34) is a fantastic car, but I also have a soft spot for the 300ZX (Z32). That car was way ahead of its time in terms of technology and design, and it's still a blast to drive today.
As for the vertical hinged door handle, I believe you're right that the 350Z was the first Z car to feature that design. It's a small detail, but it really adds to the overall look and feel of the car.
I don't think it's fair comparing cars over such a long time span. So I'm going to say that my favorite old-school Z would be the 240Z, and my modern-day pick would be a tie between the 350Z and the new Z.