Uh oh, I've detected a MAJOR new gotcha possible with Photoshop 11.0.1... It may not be considered a problem, per se, but it is definitely something that could throw you off while editing.
Sampling the image is now subject to the size you've chosen with the eyedropper tool, in ALL cases.
Put simply, if I have selected in some prior color sampling operation a 31 x 31 pixel sampling area for the eyedropper, then I hover over a pure white place, what's being shown on the INFO palette is the 31 x 31 pixel average under the cursor, which may be WAY less than white.
It seems Adobe has extended the dropper sampling area to all sampling operations.
This may have been intentional, but MAN does it invoke the possibility of making mistakes or at least confusion if you're used to the sampling being a point sample in most cases.
So: Remember to set your sample area to "Point Sample" or you're likely to get readings you don't expect.