tried p90x for several weeks once before I determined it is a program designed for people who need to have someone in front of them on the tv to hold them accountable for their workouts..
p90x: build some flexibility, agility, stay in aerobic state for ~45 minutes, lift lighter weights using functional movements for higher reps. you feel winded after workouts, even sore sometimes, but you certainly don't feel like you ripped your muscle fibers apart to make them grow.
or, cut by focusing on weight training with high reps/volume, and do 20 minutes of cardio 5 days a week. i got better results this way, most definitely retained more muscle/strength, but to each his own.