I have the p90x thing. I can see that with a good diet, and sticking with it, that it would probably work pretty well. Unfortunately, I just spent $120 finding out that I don't have the discipline to work out at home, so I got another gym membership. Brittney, two of the craziest workouts have been the plyometrics and the ab ripper x on the p90x program. The plyo is about an hour long, and the ab ripper is 16 minutes long. If you want, I'll try and burn a copy of each and send them your way.
No equipment is needed for either.