I personally really like the Power Circuit circuit segments, and the 10-10-10 warm-up, kickbox and hi/lo (the hi/lo segment is 9 minutes of pure pain, so much so that you don't notice it isn't 10 minutes!). Also, the Kickbox core / ab routine, and the All Step and Leaner Legs ab routines are very solid. And the Step Intervals interval segment is a good entree into Cathe's other step interval workouts (i.e. the I-Maxes).
A-Jock