Another dicking-around-the-interwebs discovery: Roundshape links to this amazing slideshow on Shapely Prose that matches pictures to BMI numbers. Interesting and thought-provoking.
EDIT: My sister Kathy watched the slideshow and informed me that she is "overweight." You can see a picture of her a few posts down. She's an amazing volleyball player and happens to kick ass. One of her spikes sent an opponent to the hospital.