After a year of feverish buying and selling I feel I have something to offer in this thread that also surprised me (the difference between projections after reading online reviews and real world perceptions and preferences).
Nikon F3:
Would love to love it as the best bare bones aperture priority SLR but ... that bloody LCD meter has to be the worst design misstep in camera history. Not only impossible to read quickly, destined to dim or die and unrepairable.
Nikon FM and FE series:
Toy like build. My Canon AE-1 feels better made. The pull-out film was advance lever as on/off switch for meter and shutter is the pits. I think my forehead still has bruises. Awful viewfinders, dark and lack of choice in focus screens. The F2 on the other hand reigns here, but oh, the bulbous heads. How Canon could put a light meter in the body with the F1 (1971) and Nikon could not is beyond me. Ditto what others have said here: Nikkor glass is uninspiring. And big form factors compared to FD or whatever. Owned the wonderful CV 40mm f/2 pancake and would have loved to find a body I could accept for it, but accepted Nikon not for me after much trial and patience.
Pentax SMC 67 55mm f/4:
Perfectly fine IQ but shotgun-like form factor on the already beastly 67. Plus o realised too late that I have no desire to shoot wide angle on the 67, just portraits with the 105mm. Sold it for what I paid for it.
Canon P / Canon L1:
Got really excited about affordable mechanical RF purity (and sexy for the P) with opportunity to fit with some great Canon LTM glass. But then ... no. It all just reminded me of the Leica M feel I was missing.
Billingham bags:
Lovely quality. But screams: steal me. My $5 back pack works well.
Fuji 6x9:
There is a reason why children think you are a clown. Useless for portraits.
Zeiss 35mm f/2.8 ZM:
Say whatever you want, compared shot for shot with the Color Skopar. Could see no difference whatsoever. Bigger. Slower. More expensive. Unnecessary third stop detents. No tab. No thanks.
M6 classic silver:
Looks so great on Instagram. Ah, ****. Black is so much better! Silver chrome nothing like my (now sold) M2 brass, obviously. But was not prepared for how shiny it was and therefore not discreet. Flipped it for a colour exchange. 🙂 Holding both in each hand, the silver looks bigger. Confirmation bias at work!
Kit items I sold and regret:
CV 35/2.5 Color-Skopar:
Bought another. On its way!
Canon F1 original (1971):
For me, the best mechanical SLR ever. But gave up on SLRs for 35mm.
Leica M2:
My baby. Where are you? Hopefully we shall meet again one day.