It all depends how you look at it. Yes you have all the food necessary to not need protein powder. BUT most the time protein powder is needed because there are times where you don't have the time, nor in the right place to eat food.
Example: You just finish a gym work out and it takes 30 mins to get back home, then another 30 mins to cook food up unless its already preped. If you're looking to gain muscle, its important to get protein in you're body ASAP after workout to initially feed you're muscles until you're able to eat the proper protein/carbs you need. If you don't get the protein in you're body before 30 mins after workout, you're not gaining maximum potential of muscle growth.
Personally i take a low carb Protein called: GOLD STANDARD 100% WHEY, WHEY PROTEIN ISOLATES. I take it with water to hasten the protein absorption. If you still need milk and other carbs, you can always have that later on. I usually have milk sometimes before i go to bed, not all the time though. (Everything in reasonable moderation) - You want to aim for at least 0.3/0.4 grams of protein per kilo. Example 75kg = 25-30 grams of protein per serve. To know how many scoops you need, you need to look at how much protein you're protein powder serves per scoop.
I could get into it allot more but i don't know you're frame/height/body weight and i don't know what goals you're going for.
It depends what you're looking for though. If you're looking to bulk, then get a protein powder with carbs.
Side Note: Stakes are a great food source for supporting muscle growth and many other things it assists in general. But only eat 1 big steak every 3 days. Any more then that and you can have very very long term affects with you're stomach and bowls. Not always the case but it's one sure way to help keep you're body's digestive system healthy.
I know this is vague information, but if you want to know more. Just send me a PM and i can help you with any questions you may have.