I've had my MX (my main black one of the the three I have total haha) longer than any other Pentax camera, and the more that time-span grows and the more I try other cameras of various eras and makes, the more I adore the MX.
If I shed all my bodies but two I'd personally keep it and the MZ-S. Adore the LX but I don't trust it in the way I trust the MX.
(Also, I can keep my KX because *technically* I gave it to my father so it is sort of in "off-site storage".)
Of Pentax-persuasion there is
... MX (times 3), LX, MZ-3, MZ-S, 645Nii, 67, K-3 ...
I'm pretty sure that's all I have now. Wow. Fewer than I thought. I'm good.