Hmmm... i dunno about the sweat issue not being a good judge of an effective workout. I personally strive for what I call "break through" sweat.... when I can get to the point where my body just kind of opens up and lets it all run out (one of the reason I love spinning so much!). For me its more of a catharsis. It means my body is responding correctly to a heavier cardio workout; it means I am not dehydrated. Workouts where I can't get to the break through stage tell me I probably need more H2O... less sodium... less alcohol

whatever.
I have friends who absolutely detest sweating and stick to pilates and yoga for their workouts. It works for them. Just doesn't cut it for me, tho.
Am I off target with this?