Yep, what Monger said. If you're eaten a whole-food meal within ~2-3 hours of the workout, you don't need anything else. If it's been like 4-5 hours, then it would probably be beneficial to have a protein shake ~30 min before the workout. This could be your Musclemilk, or it could be a scoop of whey with some carb source thrown in. The point being, like Monger said, is just to not be 'fasted' when you do the workout.
Also, they pitch Surge Recovery Drink pretty heavily with your P90X. The cost severly outweighs the benefits. Not that it would be BAD to have it, but you just plain don't need it. Period. Get some carbs and protein PWO and you're fine. The only reason you'd need something with a makeup like Surge (not Surge specifically, necessarily) is if you're doing multiple intense workouts a day.