What, no Orange Quangaroos? You are wise beyond your years.
*o’Froot? But it’s part of this complete breakfast!
Cheerios, Raisin Bran, Wheaties, and Grape Nuts are my favorites.
In order:
Raisin Bran (must be Kellogg’s)
Cheerios
Frosted Flakes (store brand OK)
Cocoa Puffs
Cocoa Krispies
Fruit Loops
I have a child’s tastes when it comes to cereal: Apple Jacks, Cap’n Crunch with Crunchberries, Cocoa Crispies or Honey Smacks for me, in more or less that order.
Raisin Bran
Frosted Mini Wheats
Rice Chex
I am 35 years old.
Number one for me is Grape Nuts.
Other purchases include Shredded Wheat, Cheerios, Rasin Bran, and less occasionally Corn Flakes.
I am 46 years old.
My favorite is Peanut Butter Cap’n Crunch.
I could also eat a box of Fruity Pebbles in one sitting (ask me how I know!)
Other favorites:
[ul]
[li]Golden Grahams[/li][li]Grape Nuts (and its flattened and slightly sweetened sibling, Grape Nuts Flakes)[/li][li]Cap’n Crunch *sans *peanut butter[/li][li]Life[/li][/ul]
Pour a half-pint of milk on the ground for the following that are no longer available but I remember with great fondness:
[ul]
[li]Original recipe Kix (they slightly sweetened the newer stuff, and it’s not nearly as good; the texture was also coarser)[/li][li]Buc Wheats[/li][/ul]
Full-Size Shredded Wheat, followed by Raisin Bran
I never get tired of Quaker’s Life cereal (original flavor). Great texture, not cloyingly sweet, just perfect with milk.
Raisin Bran Crunch. However they treat the bran flakes, it makes them stand up to milk longer instead of instantly turning to mush.
However, the “granola” clusters in it are extremely offputting - chomping into an unexpected difference in texture and taste when I’m half-asleep makes me think I’ve eaten a bug or something. So I usually fish out the bigger chunks, which have often fused together into one giant boulder of sticky granola, too.
You must look exactly like me… just with a goatee to indicate “evil doppelganger”. 
Love Cocoa Pebbles. Love, love, love, love, love.
However, I usually eat Corn Flakes as the box lasts longer than 18.3 hours. 
My favorites were listed above but I eat better now and what actually I eat and enjoy to a point (but couldn’t call my favorite) are a rotation of the Trader Joe’s versions of Cheerios, Corn Flakes and Rice Krispies.
I’m nearly 60, but I still like one kiddie cereal…Cocoa Krispies. The best part of CK is drinking the chocolated milk after you’ve eaten the cereal. Yum.
I also like Product 19.
But my favorite favorite of favorites is Honey Brunches of Oats.
I used to love Team flakes, but they’ve been discontinued for eons. So today my cereal of choice is corn chex, or the generic equivalent. I’d like raisin bran if they’d back off on the raisin to flake ratio.
Just dilute it with Wheaties.
Fortified Oat Flakes - no idea if they even make it anymore.
Anyone remember Stax?
I think so. They looked a little like Honeycomb, but they were wheat, right?
I don’t like my breakfast to be too sweet. I’m partial to Shredded Wheat and Bran, Cheerios (only the original), Grape-Nuts, and occasionally Grape-Nuts Flakes, Wheaties, or Puffins. I really like Kashi Golean Crisp (original), too, but Kashi Golean Crunch is a bit sweet for me.
Chocolate Frosted Sugar Bombs - the favorite breakfast of Calvin from Calvin and Hobbs fame.
I eat cold cereal about 90% of the time for breakfast. I like a lot of different cereals; however, they all have the same thing in common: 15% to 25% fiber.
The things one worries about as they get older…
I never really had an unquestionable favorite. I was always kind of a serial cereal dater. I might develop a fancy for Golden Grahams or Apple Jacks or whatever, but by the third or fourth time Mom comes home from the grocery store with the same brand, it’s probably time for me to change allegiance again. It’s been a pretty long time since I ate cereal on a regular basis. If I happen to get a wild hair while I’m in the cereal aisle these days, my selection will have as much to do with whether it’s on sale than anything else.
There’s a vaguely healthy food brand called “Nature’s Path”, and they make a nice crunchy flake cereal: Heritage Flakes. The flakes are thick and durable, and they stay crunchy for a long time after the milk goes on. Although they’re very slightly sweetened, they’re not too sweet, which I like.
Heritage Flakes with sliced peaches, yum.