The P90X program suggests taking pictures on Day 28 to compare with Day -1. While these pictures look kind of stupid since I'm trying to maintain good posture, I think they should some subtle improvement. My body composition scale tells me I've lost 3 lbs in these four weeks, all of them fat. I'd like to lose 1-1.5lbs of fat per week so I'm off target, but not by too much.
I think I have a little more definition in my torso, front and back, but you can judge for yourself.