Cool timeline! If you're interested in classic SLRs as users, rather than as collectibles, you should get a copy of Ivor Matanle's "Collecting and Using Classic SLRs." Its a great book that discusses which old SLRs are the best from the perspective of a user today. Which are most reliable, repair costs, quality of different lenses, etc. Interestingly, his favorites are inexpensive Minolta and Pentax systems. He says Nikon, Canon, and Leica are also very well made and reliable, but they're expensive. Pentax and Minolta are good and cheap!