As a grown up I ate a whole box of Kaboom in one setting. The result wasn't pretty.
Frankenberry and Lucky Charms were two of my favorite cereals as a kid. I didn't appreciate Count Chocula or Coco Pepples either.
But I also enjoyed shredded wheat and grape nuts if I managed to get to them before they got soggy. Now I like 'em okay even if they're soggy.
I disliked oatmeal greatly. It was only good insofar as it was gooed up with brown sugar. Now I love oatmeal because of how I prepare it -- cooking it with milk and fruit already in.
Malt-o-meal was my favorite hot cereal as a kid. Still ate too much brown sugar on it but it was okay without.
Just about anything with freeze dried strawberries is a-ok to me.