I love mythology, and there are so many mythological creatures to choose from. There's thousands of lesser known ones, but there's a couple that I'm fascinated with.
Phoenix: Has origins in Egyptian mythology. The Phoenix is nearly immortal, because when wounded, it regenerates incredibly quickly. When it nears its natural death, it creates a nest and ignites itself, and an infant Phoenix is created from the ashes. The Phoenix represents divinity and the power of fire.
Gryphon: Has the body of a lion and the head and wings of an eagle (sometimes a falcon). Different kinds of Gryphons show up in various cultures throughout history, including Greek and Persian mythology. The Gryphon is a majestic symbol of divine power and a guardian of the divine.
Those are two of my favorites. I'm even getting a Gryphon tattooed on my back.