As the non-extraordinary half of a romantic coupling between a superhero and an average person, the female half (and in this instance, the non-extraordinary half is usually female) can expect certain things out of life.

She will be alone for great periods; otherwise she will be chained to a building wired to explode. She will pace, frustrated with the vague sense of commitment in their relationship; otherwise she will be kidnapped and forced to have dinner with a supervillain on a luxury yacht (also wired to explode).

She will reconcile herself to the possibility of having a normal life with a superhero; otherwise she will be crying that nothing will ever be normal. She will know the secret identity of their superhero. But mostly, she will suffer.

It's part of the deal.

There is, however, an art to making this kind of relationship work — for audiences, for superheroes and for the female characters who love them. The finest practitioners make it look easy ...

PEPPER POTTS

BFF: Iron Man

Played by: Gwyneth Paltrow

Relationship: Tony Stark's girl Friday; promoted to Stark Industries CEO; a quietly flirtatious mutual infatuation; knew his father, cautiously optimistic about Tony; she seems to be game for something more, but he's a consummate playboy and prone to self-destructive behavior.

Hurdles to romance: Professional standards; Stark's narcissism, wandering eye; Stark's reliance on technology to keep him alive; her inability to remain out of danger.

Integral to plotline? Not really — and yet, without Paltrow's charmingly weightless performance, Pepper would be forgettable; indeed, it's the first time in years audiences have felt warmly toward the chilly actress. The first film, in particular, though less so with the overstuffed sequel, is a fine example of how the right actress, employing the right smirk of bemusement and pingpong rapport, can bring a breezy joviality to a role expected to get drowned out.

MARY JANE WATSON

BFF: Spider-Man

Played by: Kirsten Dunst

Relationship: Next-door neighbors; childhood friends; high school crushes; couple; not-a-couple; couple; she knows he's Spider-Man.

Hurdles to romance: She's the hot girl, always just out of reach to Peter Parker; then, when he's the Wall Crawler, she's the risk he doesn't want to take (to get to him, a villain might harm her); then she's engaged to an astronaut; then in love with Peter's best friend; then in love with Peter; then Peter stands her up; then she thinks he's cocky; then she gets frustrated; then she decides Peter Parker is the right one; then ... we forget (it's exhausting).

Integral to plotline? Sometimes. We want to believe M.J. is Integral, and certainly, in Sam Raimi's emphatic series, the "Spider-Man" movies play as grand romances, marked by sincere longing and that blush of first love — at least initially. The couple's first kiss, him upside down, her standing in the rain, is one of the most indelible movie images of the last decade. But Dunst's mugging, after the first film, grows tiring, and the character's need for a little bit more commitment from Peter seems to go nowhere. By the third film, she's been through three guys, countless near-death experiences, multiple careers. Yet the character feels stalled. She's a speed bump.

RACHEL DAWES

BFF: Batman

Played by: Katie Holmes, Maggie Gyllenhaal

Relationship: Her mother was a maid at stately Wayne Manor; spent her childhood with young Bruce Wayne; went on to become assistant district attorney of Gotham; she knows he's Batman; unrequited on-again-off-again romance; off-again after she's killed by the Joker in "The Dark Knight."

Hurdles to romance: His arrogance, need for secrecy; his intense workaholic connection with his night job; her intense desire to bring down the mob.

Integral to plotline? Certainly. Rachel is the human anchor, the normal life Bruce will never find time to know. Nevertheless, despite the character's being well-written, Holmes' portrayal in "Batman Begins" lent a very light emotional anchor (it's as airless as Paltrow is weightless); Gyllenhaal's turn, however, suggested a bit more — a character moving on, but always glancing backward.

(That said, Vicki Vale, a photojournalist played by Kim Basinger in Tim Burton's 1989 version, was pure fluff.)

LOIS LANE

BFF: Superman

Played by: Margot Kidder, Kate Bosworth

Relationship: The yin and yang of superhero lore. There's a professional distance, at first; both meet as reporters. Eventually lovers, but initially Lois is more infatuated with Superman than with Clark Kent.

Hurdles to romance: Lois' obsession with Superman, not Clark; in "Superman II," he gives up his powers to live with her as a mortal, then realizes without him as an immortal, the world dies; in the 2006 film, with Superman away for years, Lois has taken a fiance, given birth and written an editorial/awkward love letter: "Why the World Doesn't Need Superman."

Integral to plotline? Superman is arguably the only superhero whose love life is as important as his enemy. Without Lois, Superman could be an invincible cipher. With her, especially as played by the scrappy Margot Kidder, she is the potential blood he doesn't shed, his vulnerability. There's a joy between Kidder and Christopher Reeve in "Superman II" rarely seen in this genre, and that's after he forsakes his powers for a normal life with her. In the Bryan Singer film, Bosworth has a son who turns out to be Superman's spawn, though she (and the kid) feel like a distraction from Superman's existential issues.