I would say the 727. It carried me on the first flight I remember. It is the airplane that taught me some 30+ years ago to trust airplanes. Its wing was flipping considerably for me back then and I was afraid it might break. But after an increasing number of safe trips I realized it was safe to fly and help to fall in love with aviation.
Also the C-130 which took me home on my first leave during my military service. I was so happy to be airborne and away that I said it is better than sex.
Rwy in Sight