What tapes YOU would be happy with might not be the same ones that others like. FOr example, I don't like torquey moves and fast step, so I don't put many of Cathe's step videos in the top three.
My personal favorites:
Currently: Muscular Endurance; PLB/PUB; BootCamp (but this his highly influences by the fact that these are the most recent workouts!).
My favorites not including the Intensity series:
Power Hour
Circuit Max
Cardio Kicks