Man that is a tough one. If I had to narrow it down to one. I would have to pick a kit that is difficult to get. As it came out in the mid 80's as far as I can tell.
It is a Hasagawa 1/32 OA-4 M Skyhawk High Grade Series No 6. Kit #ch006:4800.
Reason being is. It comes with white metal landing gear with separate pieces for the brake pads, rubber wheels and photo etch. Albeit the etch is thin aluminum. ( I think). Complete with a labeled cut out section on the instrution sheet for the seat harnesses. And all buckles needed for the office.
You actually have to cut the nose off the fusalage halves to put the blister nose on, plus part of the tail and fusalage to get the avionics hump. So there is a little bit of everything going on in this kit.
The detail on this kit is very good for it's age. I know the made other kits in the High Grade Series, but being a jet junkie this was the only one in the only jet in the series I believe.
They are hard to find. If you can get your hands on one they are a blast to build and they look great when done.