If you are taking the whey first thing in the morning, or after training, mix it with water. The absorption is fastest with water.
If You are taking the whey throughout the day, or before bed mix it with milk, or take Micellar Casein based protein. The protein release is slower, takes a few hours to be fully absorbed. This is what your body needs throughout the day, and while sleeping.
The same goes for carbs. Pre workout= slow release carbs. Post workout (immediately after training)= fast release carbs. Then back to slow release.
Cheers. Gary.

CARBS are your friend... I took the Quick Fuel mix that GNC sells, for a week for my work outs. Then one right before my Belt test of 5 hours and I have to say it works freaking swesome. I did not feel super tired just tired like I worked out for an hour and a half.