I think there are several. "Best" can mean 'to get you into the game', 'that kept you in the game', 'that was the most fun', or a bunch of other things, like 'got you the most girls or guys' (depending upon you are, obviously).
I've owned every 'F' body from 'F to F4', and the most meaningful to me was the F, hands down. I knew that photography would be in my life with that camera. I had an F2 phototomic that I used to put me through college and postgraduate school, and 4 years of media work before I returned to active duty. One of the F2 bodies was reworked to be pin registered to do simple animation for commercial work. One F2 shot lighting fixture catalogs, shoe ads, and more - it was a tough sumabitch.
On active duty, I went into a camera store to get some supplies for our shop and wasted some time looking at some new Nikons and bought a FE2 for myself and fell in love with automated metering. (What is match needle metering but automated metering that is done by hand? ;-) ) The FE2 made + or - exposures easy. It was a champ camera. I carried it with me for years. I must have taken far more pictures with it than any the F2(s), F3(s) or F4(s), simply because it was with me.
I was one of the guys who ended up getting the retro 35Ti Cameras, too. Really took some great pictures. (Looked cooler than hell, too.) I was going to get the wider model, too. Just never got around to it. It was stolen in Barcelona.