P90X is a great program if you want to build muscle and strength. It's tough and will take a lot out of you, but if you dedicate to it, you will see results.

Now, for losing weight and getting fit - well, it may or may not be the program for you. Some people do very well with heavy weight training - me I get absolutely ravenous and end up eating to much. Some people get hungry with cardio, some with weight lifting - depends on how you react.