Thank you everyone for the ideas and thoughts, biased or not. I do appreciate them. Sometimes when it is hard to come up with an answer on your own it helps to have friends throw their opinions in the hat. Believe it or not your thoughts do help if only to make me think of things I had not considered.
In answer to a few questions, I have both M42 and K-mount because my Pentax collection included a Honeywell H1a. and a Pentax SV. Interestingly, with the exception of the ES II, I never did own a Spotmatic until just this year. I have not considered M42 in my decision making mainly because I know I can use an adapter to use those lenses on both Minolta and Pentax. In fact, I am pretty certain I have an M42 to SR adapter around here somewhere and I know I have the K mount equivalent because I use it quite a bit.
How do I use my cameras? Wow! Obviously there are all the usual suspects, Landscape, action (sports mainly), portrait, daily life and on and on. The Minolta system actually got its start because I used it to chase my kids around the baseball, soccer and football fields. The Pentax system started more as part of my real life as an accident investigator. The company I worked for at the time had a Pentax K2 so I just built off that basis. Worked very well for a long time and the image quality was always exceptional. Since I personally owned a K1000 it was easy to add things I thought I needed at the time, and practice with them, without having to justify everything on a company expense account.
I have definitely killed a couple of Pentax cameras along the way but some of them have truly absorbed a huge amount of abuse. I can't remember having any of my Minolta cameras break but there is a big difference between being able to put things back in a bag to help protect it when the weather goes south and having to keep shooting no matter what, snow, sleet, wind and rain, a few times all at the same time. I know that sounds a bit dramatic but it is the truth. Accidents rarely seem to happen when the weather is nice.
Yes, I do have several LX cameras, partly because they held up very well in bad weather and partly because I couldn't beat that exposure system with anything else I tried. And yes, a couple of them have died along the way but being dropped into deep mudholes and experiencing other forms of abuse will do that. In the spirit of full disclosure; if you ever see me advertising a used Pentax LX you may want to run the other way. All of mine have lived very hard lives! As an odd side note, I own two Pentax K2 cameras that I have used (read that "abused") in similar ways but they have always been repairable. They are not advertised as weather resistant so I'm not sure why, but they just seem a little tougher for some reason. Or perhaps I was just lucky. But no matter what anyone tells you their exposure system is not as good as what is in the LX. That camera truly is amazing. Back before we had instant digital preview it was nice to know that you could depend on your exposures and the off the film plane exposure measurement system in the LX is really, really hard to beat.
You can tell I depended on the Pentax for work but I don't want to short Minolta either. That Minolta SRT system is really stout and very reliable as well. I have some shots from old high school football games where you can see the mud flying. When there is that much mud flying around you can be pretty sure it wasn't always missing the lenses or the equipment. And though the Minolta CLC exposure system doesn't seem to get the same level of press that Nikon, Canon or even Pentax gets, it was way ahead of its time. It is no slouch when you need to get the shot. I know that a lot of you know that sometimes coming home with a picture of that slide into 2nd base can be even more important than that picture of the dented metal, the skid mark or even some blood splatter. When your kids or grandkids are looking through your contact sheets even more intently than you are you know its' important.
Sorry, I didn't mean to get that carried away but when you ask what types of things I photograph that gives you a partial idea. I guess I am no longer firing shots madly as I'm running through the mud in the end zone, or getting kicked off the field by the home base umpire while my grandson is coming down the third base line. BTW, he didn't score but he still loves that picture.
These days it is more about hunting trips, four wheeling and fishing in mountain lakes. But there are still parties with friends, picnics with family and walks down the aisle for graduations and weddings. Once in awhile it is just a quiet walk by yourself past the County Courthouse on Main Street but somehow that photo still feels just as important at the time. Don't kid yourself, I am no HCB or Vivian Maier and I know I never will be, but I do enjoy my photography. It has been a big part of my life for over 50 years. You can bet that whatever system I do keep will continue to get used...a lot.
Maybe it is time to give my Pentax equipment a rest and rely more on my Minoltas. I know they are up to it. As you all know, they are both very good systems and my poor LXs and K2s are probably just about worn out. Eric has been telling me lately that he may not be able to repair a couple of them again. But I know if Pentax ever does make a film camera again I'll be kicking myself. Besides, in the meantime I guess I still have the ES II.
Decisions, decisions.