Something that you need to consider is that some circuit workouts are more intense than others, giving you a greater cardio challenge and requiring more fuel to complete. And when you're talking about "enough cardio" you have to factor in your own fitness capabilities: what is "intense cardio" for a less-conditioned exerciser might be a warm-up for an advanced exerciser.
IMHO, Circuit Max provides the most intensity (for several reasons), SJP provides a more mid-range intensity, and Cardio Weights is the most moderate intensity. I would suggest doing Circuit Max once each week, and SJP OR Cardio Weights that same week alternating weeks. Then do 2 days of treadmill running, and one total-body weightlifting session for a 5th day. And I'd schedule in a Core Max and Stretch Max session as well.
If you've got the Terminator workout from the Intensity Series, I'd add in the Gauntlet workout during your weekly program as well. Majorly intense.
One of the tradeoffs when you're doing a circuit-style workout is that your heart rate drops while you're transitioning over from cardio to weights, and the longer the weight cycle the longer your HR stays lowered. Also, the weights used won't promote strength, only endurance. Therefore, I wouldn't stay too long (in terms of consecutive weeks) with a rotation dominated by circuit workouts. 6-8 weeks is plenty, then retool things.
A-Jock
