If you are new to weight training, then P90 is the place to start, as luvmylabs said. But if you have already used Cathe's weight training, then I'd recommend P90X.
P90 is a beginner/intermediate program. I've never tried it, but I've read a lot of posts about it, and others' experiences. It only has 4 different workouts IIRC: two weight workouts and two cardio workouts. From what I've seen on the infomercial, and heard from others, it can be somewhat boring (though others like it).
P90X is a much more complete system, with 12 total workouts, including split weight work, cardio, plyometrics, yoga, stretching, and core conditioning.
There is a fit test you can do to determine whether P90X is right for you (I think it's somewhere on the Beachbody site), but I think if you've done Cathe for a while, you'll be able to do P90X. You may have to modify some moves, and it will be a challenge, but it's doable.