What is the best tasting MRP protein shake drink?

Hands down, the the best tasting MRP protein shake is Muscle Milk flavor Chocolate. It actually tastes like chocolate milk, and not like some bad artificial flavor.  Second best tasting protein powder shake would be Labrada Lean Body flavor Chocolate.

I've tasted lots of other MRPs and in various flavors, like Myoplex, Optimum Nutrition or Monster Milk (made by Cytosport, same makers of Muscle Milk), and none of them close to the original chocolate Muscle Milk.

With that said, it will comes down to personal preference, so you should try to sample a handful of protein shakes before making a large purchase, or else you may be stuck with Protein powder shake, that you can't stand the taste of.

One of the best tasting MRP drinks that you can make yourself using Chocolate Muscle Milk, is to take one scoop of Muscle Milk, 1/2 cup (or 1/3 cup) of Whey Protein Isolete and 2 cups of Skim Milk and 3 or 4 ice cubes. This such a great tasting, after workout drink!