There's an old bumper sticker, seen around california a few years ago: "One Fin, One God, One Country"
While I'm not in any way a religious man in the normal sense of the word, I am perhaps something of a zealot when it comes to my choice of logging equipment. I know there are sound performance reasons for choosing a 3 fin board but I've never found they work for me, their more drawn out turns don't fit naturally with how I want to surf, and as for bigger waves, in the words of Tmoe Campbell, "logging is a strictly under head high trip." (Don't even get me started on progressive longboarding!)
Thinking about this the other day lead me to an interesting question: Does your choice of equipment end up defining how you surf or do you end up choosing equipment that fits your natural style? It's probably a chicken and egg question but by way of illustration...
I spent a couple of hours surfing a friend's Junod Two-tone noserider the other day. It's a very "pig influenced shape" with lots of roll, wide hips and a narrow nose. Very much a pocket noserider and a beautiful board. I tend to surf with a fairly smooth (in my own mind) traditional style but with this particular steed, the more outrageous body english I attempted, the more it seemed to respond. Fixing in my minds eye a vision of Alex Knost style theatrics, I proceeded to have an absolute blast. Suddenly I could see where his style had it's roots and I'm sure that years of getting the most out of such a shape may have helped to define his approach. Jared Mell surfs similar boards and clearly has similar elements to his style too. Musing further, it's also clear that your local waves will have a massive influence both on style and choice of equipment. Piggy logs, for example, love clean steep waves but don't noseride especially well in the mushy windswell waves we deal with so frequently.
Not a conclusive answer or a scientific approach at all but something that made me think.