+1 to tcc. I personally like the I-frames best because their relatively tiny elegance of construction really appeals to me, but of course the true I-frames went away at the beginning of your proposed time frame. I liked their relative affordability until some of us (myself included) started raving about them on this forum and started a mini-rush on them.

The K-frames of the '50s are a safe bet, especially the higher grade versions... Folks have loved and collected these for years but there are still some "safe queens" out there at affordable prices.

IMHO, the N-frames are now in two categories, investment or shooter, with few in between. The "basic" models such as the 28 and the 57 & 58 which used to draw very little collector interest... but just look at them now! There are still some bargains out there, and of course they are some good investments, but I have personally avoided the rarified heights of N-frame collecting.

The foregoing is my personal opinion and probably worth exactly what you paid for it, but you did ask!

Froggie