I have started Zumba and find that I get a better cardio workout from it than at the gym. Not only do you get excellent cardio but the sculpting and tone is really great too. You are working your whole body. For extra toning use 5-15 lbs dumb bells for extra strengthening at home. It works.
The best thing about it is you get to do it in the privacy of your own home, its a lot fun because its dancing. I've tried classes at the gym and find it too slow compared to the dvds. With the dvds you are working out with Beto Perez who developed it.
I totally love it. No waiting for machines anymore.