After a hard training session of lifting weights, the worse thing you could do post-workout is to skip out on a protein/simple carb mix.
At this time your muscles asbolutely need protein and sugar to help replace glycogen stores and help build your muscles.
NEVER skip your post-workout shake. Now, you could actually opt for a meal instead with a piece of baked chicken and a piece of fruit, for instance. But, protein shakes are a little more convenient.
I like to make mine before I leave for the gym so it is ready for me as soon as I am done lifting. I usually pack it in a cooler or sometimes I will add a lot of ice to it to make sure it stays cold.
Here is a new recipe for a protein shake that I recently came across:
8 oz water
1 heaping Tbs of sweetened Kool-Aid
1-2 scoops vanilla protein powder
Add all ingredients together, mix, shake and enjoy!