I have an ongoing, highly volatile love affair with the square.
I'm generally too lazy (or unconcerned) to crop so, neg format == print format which is either 1.0, 1.25 or 1.4. When I'm feeling ambitious, I'll go for a 1.571428571429 but, I avoid 1.61803398875 like the plague (it's cliche!).
For a while I was a fan of capturing my composition regardless of aspect ratio. I found in printing that my prints tended to fall into a few different aspect ratios within small. So I measured them to find out what they were (and had to do some research to interpret the results).
Turns out that I "see" in just a few aspect ratios. One is 4:3, which fits fairly nicely on my 5x4 film. Then there's the golden ratio ((1 + sqrt(5))/2, or 1:1.618, which works out to about 5x3. And there's a panoramic ratio I see in sometimes, about 1:sqrt(5), or about 1:2.24, or about 5x2.25
Having found this out, and also facing the problems of printing and framing if each print is a custom size, I've started to limit my prints to one of these three aspect ratios. And it's working out just fine, and simplifying my printing/framing too.
I have no idea why it works out like this for me. The human mind is a mysterious place.