From what I have read, and practice, protein sources have different usages.
Egg protein is a pretty quick protein, so immediately after my morning workout, I take 15 egg whites, some skim milk and splenda, in the mixer for a few seconds and gulp it down.
I also add a quick carb (clucose) intake with fast protein to get maximized protein uptake. Whey is the fastest protein with an action time of 30 minutes or so.
For mid morning, I do a low glycemic car source like oat meal.
Lunch, lean meat. Chicken or turkey mainly. Lean meat has action time of about 4 hours.
Afternoon workout and directly after I take a protein shake with whey protein with a good amino acid profile.
For dinner, meat. Either red or white.
In the evening, I take in milk. Why? It has effects on weightloss for me, and maintains me in relatvly good fat balance, even in my bulk stages. Lots of good calcium too. Milk also has the slowest acting protein - 8 hours.
So for me, it's a balance between eating and supplements. I still put on 1-4 lbs a month of muscle mass, so I need to eat. I try to schedule my eating to optimize for positive NO during workout and post workout recovery. I'm by no means an expert, just doing the best I can with the information I have read and snapped up on the net over the last few years.
Andy