If we are including anime and manga, then I'd say Vash the Stampede hands down. He's not really a superhero in the traditional sense, but he does have a very strange body with strange powers (which, mostly, he is rightfully afraid of). He has the ability to stop bad guys with amazing gun skills and *not* kill anyone in the process - he can dodge a hailstorm of bullets. He can destroy an entire city (again, his strange body and he does his best to *avoid* doing that). He's a technical pacifist, an irredeemable do-gooder, he couldn't live the nice, quiet life he desires "if he tried," and, believe me, friend, stranger or even enemy, he'd take a bullet for you (and has the scars to proove it).
The author/artist for Trigun (Vash's manga) makes absolutely no secret that he's inspired by American superhero comics. It's well known among Trigun fandom that he attends Comic Con every year.
Still, because of the circumstances of his story (both anime and manga versions) I'm not sure Vash qualifies as much as a "superhero" as much as he does a "tragic hero."
Beyond that... as far as traditional superheroes go, I gotta go with Batman. I haven't read much in the way of the comics, but I was a fan of The Animated Series, the movies, and the general mythology that everybody knows. What I love about Batman above all is that he *doesn't* actually have superpowers - he just uses a lot of gadgets and inventions and, above all... his BRAIN. I love his amazing detective skills - he cannot rely on strength like, say, Superman - he uses his incredibly sharp mind in everything.