Hi Judy,
I, too, came from the FIRM to Cathe. So...
Let's see, it looks like you have (except for the Terminator) mostly strength type workouts. Maximum Intensity Strength and the Pyramids. I don't have the Terminator, but I've heard that it combines alot of the IMAX2 -- anaerobic interval training. But since I don't own that one, I can't say for sure.
So Maximum Intensity Strength and the Pyramids are great strength workouts -- you might want to add a couple more cardio and anaerobics -- depends too on what you want to emphasize -- and this can change from month to month.
Some good basics -- and I highly recommend you get and read, READY, SET, GO! by Phil Campbell -- he just goes over the basics so that you really GET them -- but some good basics are:
1) you have three different sets of muscle fibers -- the slow twitch, and two different fast twitches. Different exercises work different muscle fibers. To work all muscle fibers, you need to vary your exercises a bit.
2) Overall exercise should include 5 different things each week -- anaerobics, cardio, strength, plyometrics (jumping), and stretch. Anaerobics works the fast twitch muscles -- as does plyometrics -- these two (and some kinds of strength work) are the only kinds that I know of that will actually work the fast twitch muscle fibers. Most exercise (and this includes cardio and most exercise videos) work only the slow twitch.
3) standard cardio and strength work the slow twitch muscle fibers
4) stretch is important as it helps keep you from injuring yourself and does other good things.
Okay, so what this means is that to get the best from exercise, you should try to incorporate into your workout those things which each week will work all three different sets of muscle fibers.
That's why a good balance might be 2 anaerobic days, 2 pure strength days, 1 cardio day and one plyometric day -- and on your day off -- stretch.
So, I don't have all of Cathe's videos (I have none of her Kickboxing -- and so I can't evaluate those as to whether they are anaerobic or straight cardio). But the IMAX's -- IMAX, IMAX2, IMAX3, LowMax -- all are anaerobic/plyometric plus cardio in my estimation.
Muscle Endurance, Power Hour, Muscle Max, Maximum Intensity Strength, the Pyramids are ones that I know are pure strength workouts -- there's probably more...
High Step Advanced, BootCamp, Cardio and Weights, Circuit Max pretty much are cardio, some anaerobics, plyometrics and strength -- all in one workout.
Cathe's step workouts are pretty much cardio endurance. And now Cathe even has a stretch DVD.
So if I were going to recommend anything, I think I'd recommend that you get the Intensity series. That's really a well rounded series that you can rotate with what you already have. Plus, I'd get one of Cathe's step workouts for a pure cardio workout -- there's many to choose from. Sorry I can't tell you about the Kickboxing because I dont' have any of those workouts.
But if you get the book, READY, SET, GO! and read it, maybe you can tell me if they are mostly cardio or cardio plus anaerobics.
I hope this helps. :7