Mine is a bit different than the "standard" breakfasts I see around this forum.
Right now my breakfast consists of miso soup with tofu and wakame (seaweed) , one packet of instant oatmeal made with with soymilk and half a grapefruit. I eat at ~6:30 and I don't get hungry until ~11 or so, depending on the day.
I love the miso. It is a traditional breakfast, and very filling, even without adding the tofu or wakame, but the tofu adds more solid substance and extra protein. I think a lot of people under eat at breakfast, or eat to many carbohydrates with too little or no protein/fat at all. Cereal leaves me ravenous in ~30 min, even if I eat half the box. I drink soymilk because I don't like the taste of real milk, not because of any magical nutrious properties soy has. As for grapefruit, I will probably change that to a different fruit, like oranges, even though I really like it, because it interacts with the birth control pills I'm taking.