Ok, mind you - I am VERY new to this. I work out almost daily in the evenings (class in the morning, work afterwards)... So I guess I will be messing around here and there.... until I get it and understand it....
What you ideally want in a meal is a quality balance of complex carbs (like oatmeal), lean protein (eggs, turkey sausage, protein shake) and healthy fats (peanut butter, fish oil caps, etc.)
An example of the type of breakfast that has been working for me (and keeping me from being starving later in the day) would be a protein shake (made with water), a banana and a pice of whole grain toast with crunchy natural PB on it. that works out to about 450-500 calories, depending on the type of bread and the amount of PB I use on it and that fits nicely into my calorie needs for the day.
I try to eat a piece of fruit with breakfast, lunch, mid-morning and mid afternoon snacks and veggies with dinner and lunch. Mainly I go with apples, bananas and oranges since they are easy to transport and eat on the go. the fruit has enough sweetness to fix my sweettooth cravings and has tons of fiber, which is a good thing.
You want to really eat as much real food as possible (versus shakes and meal replacement bars). shakes and bars are more convenient, but they tend to be more expensive and less nutritionally complete in the long run than whole foods.