Eh, pretty much the way he came to be (because of the death of his parents), and being one of those superheroes who has/uses high tech gadgets instead of superpowers (not that I have anything against the opposite). Granted, there are other non-superhuman characters like Karate Kid that have beaten Batman before, but I suppose the reason he's one of my favorites is the overall dark theme/personality surrounding him.
Edit: And because his series has some of my favorite villains ๐ (Joker, Two-Face, Ra's al Ghul, the Scarecrow).
Oh, and Superman's up there on my list too of course. After all, aside from his various feats and what not, he's like, the very definition of what it is to be a hero; everyone else (including Batman) is just playing the game.