Well best case scenario I would go to the trouble to get out a blender and make a shake with ingredients that I think are optimal: oats, banana, natural peanut

Well best case scenario I would go to the trouble to get out a blender and make a shake with ingredients that I think are optimal: oats, banana, natural peanut butter, whey protein, or a number of other ingredients that cover my nutritional needs in "shake" form. If I'm in a hurry I've picked up meal replacements from the store, but most have sugar alcohols, sugar, or other processed ingredients that are fine once but you don't want all your meals like that.