Hi,
I just saw your thread. If I can offer my humble opinion I'd recommend Low Impact Circuit, Circuit Max/Cardio Kicks, and CTX there is a ton of variety and are all good and you can choose to do different areas in the chapters on all of them for a shorter workout for example in CTX. There are premixes that are great in Low impact Circuit and the music is great as with all of Cathe's dvds. I know there are no premixes on Circuit Max and Cardio Kicks or CTX those are older but still a gem of a workout but they are before premixes. I recommened a few for you with a variety because I don't know what your preferences are. If I were new to cathe and wanted to add to the collection and money and max variety for the dollar I'd go with CTX which is super reasonable now, I think its like $30 off from the original price of I think $80 but that's only from cathe.com, so I'd get it there. Also don't be worried about Cathe's older workouts not being as effective, trust me Cathe's workouts are always effective and timeless the instruction is rock solid and so is the technique, you can't go wrong with any of her workouts. I would also recommend Circuit Max and Cardio Kicks they are on one dvd together. Circuit workouts are fun and I love kickboxing myself. I'm a huge fan of variety and I own the dvds I recommended. I also would direct you to view the video clips from Cathe's website as hers are longer there then anywhere else and give you a good feel for what the workouts are like and tells you what equipment you'll need and premixes. I'd say most important is to know what kind of workouts you enjoy, your time commitment, and equipment you have available, and what health considerations if any you'd need to take into consideration, and last but not least what are your fitness goals. Exercise can be fun if you do what you have fun doing and if need be make the workout work for you if you need to modify. Just have fun and be consistant, that's the key to exercise!
Hugs!
Nora