Originally posted by Hound Tooth Yep, P mode can do everything the Green mode does, including AWB, Auto-ISO, and all that jazz. And with a quick flick of either front or rear control dial, you'll be able to flip into Av or Tv mode on a whim without changing the mode dial itself, and return to P mode by pressing the Green button. The Green mode on the dial is useless and redundant. Its only real purpose is for passing the camera to a photography ignorant so he can take a picture of you.
Actually, there are some subtle differences between the green mode and the P mode. See for yourself taking some low-light natural light photos. For example, I have my ISO set at 100 as a default. In P mode, the camera will select a very slow shutter speed which will reveal hand-held shake, while in green mode, it will boost the ISO as high as 3200 and allow a hand-held shot. In daylight, this will make no practical difference, but for a quick low-light shot, the green mode is superior. Again, for quick off-the-cuff shots, green has utility, and can be fine-tuned in PP by opting for a RAW file with the AE-L button.
John