You guys are ridiculous with your "yolk" pushing on everyone.
Simply put, egg whites if you're looking to cut or drop weight, whole eggs if you're bulking and a few whole with mostly whites if you're maintaining.
The problem is that there isn't much protein in a single egg, white or whole for that matter so you will need to consume a decent amount. I've been on diets where I'd be drinking a container or two of pasteurized liquid egg whites a day. The taste isn't bad, similar to a glass of skim milk I thought. It's much easier to down than a bunch of cooked egg whites.