I reckon the R34 looks the sexiest, followed by R33 then R32.
R31 = I just want a skyline, even though it is a pos
R32 = completely out of date, interior looks like a vn commodore. Its just plain and simply old.
R33 series 1 = ugly ass front (standard), especially when the headlights go yellow
R33 series 2 = I found it looks much better than the series 1, has awesome lights and meaner lines.
R34 = A little boxy but who cares! Love em
As for wow factor, i reckon that it no longer exists with skylines. Back in the day you would see a skyline and think "wow". Now you look at one and go, oh another skyline...