I use parts of P90X, it's very high paced, varied, offers stretch, balance and yoga excercises as well (try the yoga, it's killing).
It doesn't go for the quick fix route, but tells it like it is: consistency, and hard work.
I've been able to maintain my muscularity, tone up a bit and get my a bit dryer (around 10% BF I'm guessing) on doing mostly P90x style excercises, I did add some extra squat and deadlift variations because I felt those were lacking.
It's not a bodybuilding program, but very useful for general fitness and may get you to a decent athletic build.
BTW doing the full program requires a decent level of endurance and fitness as a starting point.
So in closing: it's not revolutionairy but it's pretty complete and varied.