#1 Kraken
A terrifying force from the deep, massive and awesome when in action. Just imagining some monstrosity rising up from the unknown depths raising its massive tentacles to drag anything down there = Wow. In a way they represent the overwhelming scale of the ocean, and its fearsome power. The fact that they have a beak just makes them cooler.
#2 Dragons
The variety found here is insane. They're some of the most aesthetically impressive creatures around. Multiple headeds, gaping stomach-mouths filled with needle teeth, etc... There's a type of dragon out there for you.
#3 Werewolves
A hulking monstrosity more than the sum of its parts. If it doesn't turn you into meat confetti, you're damned to become one of them on a regular basis. You're either robbed of your life or your humanity, not to mention you become a danger to your family and friends. So you also have an element of tragedy there, especially if a child becomes one of them. Werewolves are horror layered upon horror. My favorite type are the musclebound wrecking machines rather than wolves that talk.