Today, we enter the Final Four round of our Superhero Showdown — our ultra-mega-championship to decide which costumed crimefighter is the greatest superhero in comic book history. Today, we need you to vote in a match-up that, in many ways, defined the mainstream comic book industry for decades. In one corner: Superman, the original DC hero, a handsome image of All-American(-by-way-of-Krypton) invulnerability. In the other corner: Spider-Man, the defining Marvel hero-with-personal-problems, a creepy-cool image of urban adolescence run amok. They make ideal counterpoints. Superman flies over Metropolis, observing crime from on high like a candy-colored demi-god; Spider-Man swings through the tall shadows of Manhattan. Superman was born on a distant planet and raised on the rolling plains of Kansas; Spider-Man comes from Queens.

Check out our mini-bios of today’s competitors, and scroll down to vote now in the Spider-Man/Superman match-up. Be sure to check back tomorrow for another DC vs. Marvel showdown between Batman and Iron Man — a pair of superheroes who, in the last decade, have arguably usurped Spidey and Supes as the industry’s standard-bearers. And to get a look at how our tournament has gone so far, click on the image below for a full-sized printable bracket.

Image zoom

Name: Superman

Origin Story: On a dying planet, a child is shot into space by his parents, given a chance at a new life on in a faraway place. The orphan’s ship crashlands in Kansas, where he’s discovered by a childless, utterly American couple. Oh, and when he grows up, he’s faster than a speeding bullet, more powerful than a locomotive…

Costume: You could argue that all superhero costumes are just riffs on Superman’s iconic look: The bright colors, the cape, the color-matched boots and exterior underwear.

Coolest Power/Ability: Anything you can do, Superman can do a million times better. He’s superstrong. He’s superfast. He can fly. But Supes also has a whole array of more subtle powers, and of that bunch, it’s hard to argue against the eternal usefulness of heat vision.

Defining Stories: Alan Moore’s “Whatever Happened to the Man of Tomorrow,” and Grant Morrison’s “All-Star Superman” are both fantastic modern explorations of the Superman myth — at once playful, deconstructive, and tragic.

Cultural legacy: Superman is the foundation for pretty much the entire superhero genre. Many major characters that came after him directly riffed on his iconography. (Just look at the number of characters on our bracket who grew up as orphans.) Richard Donner’s 1978′s Superman movie established the basic template for the superhero-movie — a genre that has now conquered Hollywood. Superman is also one of the most famous fictional characters ever. In the last quarter decade, though, Superman’s actual cultural influence has been significantly eclipsed by his darker, grittier, less impenetrably invincible buddy Batman. Can next year’s Man of Steel return the character to his past prominence? —Darren Franich

Image zoom

Name: Spider-Man

Origin Story: Gawky, geeky New York high schooler Peter Parker gets bit by a radioactive spider (altered to a genetically modified spider in later reboots of the character), and overnight becomes imbued with the arachnid’s heightened strength, agility, perception, and velcro-like grip on practically any surface. But he’s still just a hot-headed kid: When Peter blithely neglects to stop a thief, the lowlife winds up murdering Peter’s Uncle Ben — the only father figure he’s known. Peter’s grief propels him into a life of crime fighting, driven by the principle that with great power comes great responsibility.

Costume: A red-and-blue unitard covered in webbing and with a stylized spider on the chest. Unlike almost every other A-list superhero costume, Spider-Man’s head (and therefore his identity) is completely covered, with two large arachnid-like eyes the only things delineating a face. It is simultaneously one of the silliest and most realistic superhero costumes ever, in so far as it actually protects Spidey’s secret identity.

Coolest Power/Ability: Hanging out on the ceiling is damn cool, and that hyper-sensitive “spidey sense” sure comes in handy. But what makes Peter more than just your average teenager is his keen engineering acumen, which enables him to conceive and fabricate the web shooters that allow Spider-Man to sling himself through the high-rise canyons of New York. (The Sam Raimi Spider-Man movies made the web-shooters an innate function of Peter’s powers, a fanboy heresy rectified in this summer’s franchise reboot, The Amazing Spider-Man.)

Defining Stories: There have been so many variations on Spider-Man over the years, it’s hard to know where to begin. But “The Night Gwen Stacy Died” — the Green Goblin drops Spidey’s girlfriend from a Manhattan bridge; Spidey shoots his web to save her; but the whiplash from the sudden stop snaps her neck — remains one of the most shocking arcs in comic book history.