That is surely a subjective answer.
My list of Pentax "Must Have's" was so long that fifteen years ago I resolved to "Must Try" each of them for a while. eBay and the Marketplace have made that possible - I'm now down to "sure, I'll try that" cameras. For some silly reason black paint mattrered.
These are the ones from my original list that were the most satisfying: K,
SV, SP-F, K2DMD, K2,
KX, MX,
LX,
MZ-S. As you can see I run counter to trend. For the most part I found the M bodies small and fussy, and I like the K bodies better. The ASA ring on the K2's never bothered me. I have little use for the K1000 - I much prefer the KM and KX. The MZ-S is my current new toy and I'm having fun using my F and FA lenses with it.
Bold are the ones I MUST KEEP. That, of course, suggests the next thread -
"Must Have" Pentax Lenses, because they're differeny for each camera.
Colton: Don't take me there. I'm not even going to look at that