I did P90X with Paleo and LeanGains and saw great results. In the beginning I just used resistance bands because I was traveling alot for work. But then I was able to switch to using adjustable dumbbells and thats when I saw even better results. You can definitely use P90x as a base and modify it for whatever results your looking for. Less reps more weight at a slower pace to build more muscle or higher reps faster pace to burn fat. It just depends if you want to workout at home or at a gym. I didn't have access to a gym for a long time, so that decision was made for me. I went from 30% body-fat down to under 8% loosing around 50lbs in the process and putting on around 4lbs of muscle. You can check my before and after pics if you like.

I did a full 90 days of p90x lost a bunch of weight (50 lbs pre primal-20 more after primal) and put on some nice muscle. From then on out I mostly did the lifting days and rested on cardio or went for a bike ride. I tried jumping back in doing a p90x insanity hybrid and a week short of finishing those 90 days i injured myself causing a pinched nerve in my back that has caused all sorts of horrible problems that I am still dealing with 6 months later. While some Primal folks might scoff at the thought of doing that much cardio I did see some benefits. Not to mention I kind of enjoyed insanity...in some sick twisted self torture kind of way.

I do Crossfit 3-4 times a week. It combines all strength training with metabolic conditioning.

You only need weight training in my opinion.

I haven't done any cardio (if you discount my 6-8minute warmups) in the last 18 months. I train 3 times a week (squats, deads, bench) following the 5/3/1 routine. I do 3-4 accessory exercises only, and these are bodyweight as far as practicable (pullups, pressups, dips, depth jumps etc). Each session takes me around 2hrs including 20mins warmup/ stretching, and 20minutes warm-down/ static stretching.

One thing I would recommend to you is what westside calls GPP (general physical preparedness) - on each training day one of the accessories I perform will be a heavy-weight-endurance type exercise, that will really get my heart pumping. For me this is usually either Farmers Walks with a couple of 100lb dumbells, or powercleans with around 150lbs (both for max reps/ time)

All told, my 'activity level' is about 4-5hours a week tops. I do paleo and leangains (IF), my bodyfat is currently around 9-10% (despite being on a constant calorie surplus :P), and if I want to run a 10k I know I could. Don't see the need for cardio or 'circuit' training :)

P90X is weight training and cardio combined with all 12 dvd's. It's a total fitness program and you can adjust your program as you see fit.

When you achieve half way of this weightloss system, your own body will take energy source maximizing so that you can resume the system until its finish. The stage 2 of P90X workout routine strategy is made to perform exactly the same necessity. Therefore, the stage 2 diet for P90X comes with a great blend of glucose and proteins. You simply must take a reduced amount of fat throughout this step. The food items on this step must include 40% carbs and 40% healthy proteins and 20% fat. This kind of cycle may last from 29th till 56th day of the diet regime.

The level 3 of P90X diet system is the stamina booster stage which highlights on minimal essential protein and fat usage and a very good carb absorption. As it is often the strength stage, it is quite simple to employ through the last events of this weight reduction process. Execution in this eating strategy along with the specific P90X exercise plan will lead you towards a well-balanced and shocking levels of fat burning. Foods which in turn you ingest within this stage need to have 60% glucose and 20% meats and 20% excess fat. This part usually lasts right from day Fifty seven to day Ninety of the diet regime.