About two years ago I started the switch from and almost-all-the-time color photographer to an almost-all-the-time black-and-white photographer. It wasn't an instant "aha" moment but the culmination of several factors that were part of my shooting style.
First and foremost was my belief that sometimes color gets in the way. By this I mean that when an image is dominated by color other aspects of the photo aren't as easily explored by the viewer. For instance, look at the image of a flamingo below:
The beautiful salmon color is what you see. By turning it into a black-and-white image now you can focus on the intricacies and patterns of the back feathers and the texture of the neck feathers.
I became a photographer after a career as a graphic designer. My sense of composition had already been honed for many years. As was my love of graphic details. Working in black and white was, to me, a natural extension of that. Case in point, the passion flower. What an incredible-looking flower!
It seemed like a shame to uncolor it but when I did all of a sudden I saw the all the glorious elements that composed it. Those great, tendril-like petals and the proud stamen looking skyward. All the very cool parts of this flower made a totally different statement when it could be seen graphically.
Of course, there are times when nothing but color will do. I would never want to be hampered by only doing one or the other. But at the moment I am "seeing" more clearly in black and white.