I don't think I need to elaborate here. Look for products with Ion-Exchanged Whey Protein, partially predigested whey fraction. If you're sensitive to aspartame look for products with Acesulfame-K as it's sweetener. The reason to take creatine monohydrate is to increase your ability to generate anaerobic power.
Anaerobic power is what drives maximum gains in training stimulus.
Creatine, in some individuals, increases the muscles' ability to generate peak torque during a muscle contraction. It does this through increasing anaerobic ATP production in simple terms. ATP, for our purposes is the high-energy compound that is utilized during muscle contractions. The more torque you can generate during a contraction, the more stimulus the muscle receives. Creatine will enable you to train harder and quicker, and to a lesser degree, faster and longer at higher than normal intensities.