So I'm in my bed in relative darkness, PB in front of me, reading an article. I set the screen brightness to ~20%... Then I switched on a light *and it adjusted the brightness setting to compensate*! Then I turned the light off *and it adjusted back*. All this time, the actual brightness slider hasn't moved!
This little thing is FREAKING AWESOME Brightness isn't an absolute, but always a setting relative to the light in it's surroundings!
Another small happy moment brought to me by the PlayBook