Typically a 2/1 or 3/1 carb/protein ratio is best post-workout. These numbers depend on your weight, body fat and of course goals.
Whey hydroslate is best post-workout. If this is not available whey isolate is next. Of course the best protein is the one you absorb.
This may be gross, but if you have gas following a protein shake you did not absorb much of the protein.
Chew your protein shakes to increase absorption. All digestion starts with the release of saliva. Weird, but great tactic to increase absorbtion of liquids.