Cereal has always been a part of my diet. It's cheap and easy and I can eat it at any time of day.
Back when I was a kid, the best were Count Chocula, BooBerry, and FrankenBerry. One of those last two was always rare where I lived, so it was always a nice treat.
Now that I'm a little more conscientious about my teeth any variety of Chex will do (or similar type).