Ankylosaurus! Tail club, armor plates, what's not to love?

I'm boring, and still like Stegosaurus best. Gotta love that Thagomizer.

I just have a soft spot for triceratops.

Spinosaurus!

Gigantic crocodile-faced sail-finned bitey boy supreme.

Patagotitan mayorum. I think that it's the largest that we know about - around 40m large. Herbivore, I can't help but think on it as a dino-giraffe: eating leaves, nesting its eggs, not giving too much of a fuck about the small critters nearby.

I love this question! This made me really happy. My favorite has always been (and remains) the brontosaurus. (Probably can blame "The Land Before Time" for its influence.)

I remember in the early/mid-90s being corrected that brontosaurus wasn't a dinosaur species, but was actually the same as apatosaurus. Being a stubborn child, I refused to accept this and always considered the brontosaurus, not the apatosaurus, my favorite. I felt so vindicated when the study came out in 2015 that brontosaurus and apatosaurus weren't the same.

Perhaps that's why I still stubbornly refuse to let go of Pluto: the minute hope that my favorite planet will be recognized again someday. Alas.

Chicken.

At the risk of sounding like a basic bitch, I'm going to go with T-Rex. Sure he has ridiculously silly arms, but he gets a pass because he could bite through a car. It's a prime case of be careful who you pick on in school.

I know they're not dinosaurs, but I like pterosaurs a lot. Their wings look cool and I bet a flock of them in the sky would be a crazy sight!

Parasaurolophus has been my favorite since I was 6 years old. I've always thought their cranial crests were very cool.

Pachycephalasaurus has always been on of my favorites.

https://en.wikipedia.org/wiki/Pachycephalosaurus

I grew up in the 80s and 90s, so probably one that isn't considered a dinosaur anymore.

Chicken.

I just killed my back for the day making a barbeque bath for their little fingers...

Wicked Barbie Srirachasaur

Archaeopteryx - apparently the first bird ever

gotta go with the velociraptor, Little knife chicken

Allosaurus

Euoplocephalus, because I like me some ank memes, but I wanna be special.

If we included pterosaurs, then anurognathus, because look at him!

It's always been Allosaurus

tricerytops

This post made me think of Napoleon Dynamite for some reason. And I loved that movie.

I've always been partial to the Spinosaurus. Ain't no cowboy gonna ride ol' spiney.

If we are accepting non-dinosaur but ancient creatures, my favorite is the anomalocaris :) it's just a goofy lil guy with a mouth snoot. Plus, they never say no to a snack. (They're at the end.)

Mine is the Pachycephalosaurus. I love it so much I use it as my profile picture. I got attached to it because cranidos is my favorite pokemon.

Therizinosaurus! When I saw the previews for the new Jurassic World movie and they teased it, I got chills. I was so stoked.

Styracosaurus. No idea why other than they just look cool as fuck!

Just want to give props to OP for playing the role of host/MC very well.

Stenonychosaurus (née Troodon) because as unlikely and silly an idea as it was I always found the whole "how intelligent could they have become if they hadn't gone extinct" thought experiment fascinating.

I also have a soft spot for Struthiomimus just because it's such a fun word to say.

Oviraptorosaurs!

They're basically giant turkeys!

Iguanodon.

Where it all started.