It would have to be K1000. I've had an ME Super that I used intermittently for over 20 years, but had to go ahead and put it up on the shelf. It needed one more repair; I got that done, and let it retire. K1000 is a pretty good, sturdy all mechanical camera.

I've recently picked up a couple of old Spotmatics for restoring; while I probably won't keep all of them, I think that design deserves a mention. 35+ years old and still going strong.

Overall, though, I favor my medium formats a little more than the 35mm; but 35mm has always been a strong contender. Given the decrease in 35mm camera production, I think we're going to see a rise in the favoring of all mechanical, or mechanical-capable, cameras.