Let me ask all you manual people: Do you use the light meter on your camera, or do you eyeball the exposure?
Chances are, if you use the camera's meter, you're doing the same thing as the rest of us in Av or TV mode. They do carry more flexibility with changing exposure, and when we're chasing our kids around. I readily use the EV to get my picture to look the way I want it to, and within 3 stops, the results are about the same. Over time, you learn a few things, like underexpose by 2/3 stop when looking at darker folliages, etc. That's the same decision you're making when you choose to "underexpose" on M what your meter is telling you.
Let's say I'm doing portraits, I'm usually in Av mode, to control my DOF. As long as my shutter speed isn't too slow, that's fine with me. I'll even leave the ISO in auto, to give the camera flexibility with this. If I find that my shutter speed is too slow in general, then I'll take over the ISO and bump it up myself. Vice versa if I'm trying to slow the shutter down.
Same goes for action shots, except that I'm doing it in Tv now. If I don't like my typical aperture calculated by the camera, then I'll take over the ISO myself and choose accordingly.
Even in flash, I'll readily use TTL with either Av or Tv, or manual
, but I'll add or subtract flash power to get the look I want.
Even in manual mode, if you leve your ISO in auto, then the camera will find the "correct" exposure for you, and then you can adjust accordingly based on your previous shot. When the lighting is ALWAYS the same (such as shooting in a studio), then manual makes the most sense. But if I'm shooting at a dark shadow in one moment, and into the sun the next, I find manual to be too clunky for those purposes.
I realize there are car afficionados out there who love their stick shift, but why not take advantage of the dual clutch auto and all the extra speed it gives you