Jet Li, Dolph Lundgren, and Sylvester Stallone in 'The Expendables'
What will happen this weekend at the box office with the mighty melee among three equally powerful newcomers: 'The Expendables,' 'Eat Pray Love,' and 'Scott Pilgrim vs. the World'?

The moves are all so different, in terms of genre, star power, gender appeal, age appeal, filmmaking style, marketing campaigns and the way they've timed their entry into the marketplace. It seems like a toss-up whether the victor will be Sylvester Stallone and his band of veteran action heroes, Julia Roberts and her romantic travelogue or Michael Cera and his comic book/video game fantasy.

There are a lot of different angles with which to approach this week's predictions, each of them fascinating. In the end, there can be only one victor; after you weigh all the factors, see if you agree with Moviefone's pick and the reasoning behind it. Jet Li, Dolph Lundgren, and Sylvester Stallone in 'The Expendables'
What will happen this weekend at the box office with the mighty melee among three equally powerful newcomers: 'The Expendables,' 'Eat Pray Love,' and 'Scott Pilgrim vs. the World'?

The moves are all so different, in terms of genre, star power, gender appeal, age appeal, filmmaking style, marketing campaigns and the way they've timed their entry into the marketplace. It seems like a toss-up whether the victor will be Sylvester Stallone and his band of veteran action heroes, Julia Roberts and her romantic travelogue or Michael Cera and his comic book/video game fantasy.

There are a lot of different angles with which to approach this week's predictions, each of them fascinating. In the end, there can be only one victor; after you weigh all the factors, see if you agree with Moviefone's pick and the reasoning behind it.

The Stars. Stallone may no longer be enough to carry a big-budget action picture on his own (though his recent reboots of 'Rocky Balboa' and 'Rambo' were modest hits), but he makes up for that by cramming 'The Expendables' with about a dozen other action stars, both old (Mickey Rourke, Dolph Lundgren, Bruce Willis, Jet Li, Steve Austin) and not so old (Jason Statham, Terry Crews). Bonus points for getting a certain California governor to take a break from his day job to shoot a cameo.

Roberts' star power isn't what it once was either (see the poor returns for 'Duplicity' and 'Charlie Wilson's War), but a female-friendly star vehicle built around her should play to her strengths. After the successes of 'Juno' and 'Superbad,' Michael Cera sorely tested his cult fanbase's goodwill with 'Year One' and 'Youth in Revolt,' but as with Stallone and Roberts, he seems to be starring now in a project tailor-made to his persona.

The Men.
Sure, it looks like a chick-flick vs. two guy flicks, but it's not quite so simple. For one thing, James Franco and Javier Bardem both bring appeal to men and women alike into 'Eat Pray Love.' 'Scott Pilgrim,' for all its action trappings, seems to acknowledge that women are big fans of comics and video games, just like men; nonetheless, this one is still pretty much about the guys. (Mary Elizabeth Winstead is lovable, as usual, as the mysterious object of Scott's affections, but has she ever sold a single movie ticket?) As for 'The Expendables,' it seems to be as testosterone-fueled as advertised, with hardly a woman in sight.

The Nostalgia. 'The Expendables' most clearly plays the nostalgia card, with its vintage cast and '80s style group action heroics. Unfortunately, that sensibility didn't really help 'The A-Team' or 'The Losers.' 'Eat Pray Love' also makes a virtue of its star's long history; viewers pondering their own midlife crises have followed Roberts for 20 years on screen as she's matured gracefully into middle age. Even youth-oriented 'Scott Pilgrim' displays nostalgia for ancient video games (Pac-Man, Super Mario Brothers, Q-Bert) that are older than Michael Cera.

Julia Roberts in 'Eat Pray Love'The Books. 'Eat Pray Love' expects to have a huge built-in following from the readers who made Elizabeth Gilbert's memoir an enormous best-seller. The readership for Bryan Lee O'Malley's 'Scott Pilgrim' graphic novel series is a lot smaller, but should bring in at least a cult of fans. As for 'The Expendables,' it seems to be made for people who don't put much stock in book-reading.

The Genres. 'Expendables' is pure action; 'Eat Pray Love' is not just romance but also a travelogue, a combination that's done well in movies from 'Under the Tuscan Sun' to this year's 'Letters to Juliet.' 'Scott Pilgrim' splits the difference with both action and romance.

The Directors. Having directed himself in 'Rocky Balboa' and 'Rambo,' Stallone is on a roll as director of 'The Expendables,' though it seems a more ambitiously-scaled effort than those last two films. Ryan Murphy is on a roll as the creator of TV's 'Glee,' which is how he's being sold regarding his direction of 'Eat Pray Love.' Which is good, because no one would go see a movie touted as "from the director of 'Running With Scissors.'" 'Scott Pilgrim's' Edgar Wright has massive fanboy cred as the director of such genre spoofs/homages as 'Shaun of the Dead' and 'Hot Fuzz.'

Michael Cera and Mary Elizabeth Winstead in 'Scott Pilgrim vs. the World'The Good Buzz.
'Scott Pilgrim' has the most intense advance buzz, thanks to Universal's months-long marketing campaign that included a variety of character posters and a full court press last month at Comic-Con. 'Eat Pray Love' has been the subject of glowing preview articles for months, thanks to existing good will for Roberts, Murphy and Gilbert's book (which has been reissued with a picture of Roberts on the cover). 'Expendables' has made much of its dream-team cast, though the Arnold Schwarzenegger cameo teased in promos reveals pretty much his whole performance.

The Bad Buzz. Does 'Eat Pray Love' live up to the hype? Hard to tell, since Sony has been reluctant to screen it for critics, though that itself is not a good sign. Meanwhile, there are worries that 'Scott Pilgrim' may be overexposed, that its hype peaked too soon, while at the other end of the spectrum, Lionsgate has not had the all-stars of 'The Expendables' making the publicity rounds much, so that one may be underexposed.

The Marketplace. 'Eat Pray Love' has the most wide-open market, since there are hardly any other female-oriented movies at the multiplex. (Does 'Step Up 3D' count?) 'Scott Pilgrim' is going to be fighting for action-comedy fans against last week's champ, 'The Other Guys.' As a pure action play, 'Expendables' is competing against the less macho 'Salt,' 'Inception' remains a wild card, as an action thriller with appeal to grown-ups and genre fans, that could siphon viewers away from any of the new movies. All three newcomers are smart counterprogramming against the family fare that's dominated the summer and that's still occupying theaters in the form of 'Toy Story 3,' 'Cats & Dogs: The Revenge of Kitty Galore,' and 'Despicable Me.'

The Sibling Rivalry. Eric Roberts has a supporting role in 'The Expendables,' making this the first time Moviefone can remember that he and his younger sister have gone toe-to-toe at the box office. For good measure, Eric's daughter Emma Roberts is in theaters, too; her indie drama 'Twelve' is playing on a handful of art house screens, having opened last week.

The Theater Counts.
All other factors being more or less equal, this is where the three-way battle will ultimately be decided. 'Expendables' is opening the widest, on 3,270 screens, which is why most pundits expect it to win, with a debut around $30 million. 'Eat Pray Love' is opening on 3,082 screens; its projections range from $22 to $28 million, but it's sure to finish in second place. 'Scott Pilgrim' is opening on 2,818 screens; it should battle for third place against 'The Other Guys,' still playing on more than 3,400 screens. Both films should earn around $17 or $18 million. 'Inception' still has a strong theater count of more than 3,100 screens, but it's in its fifth week and should earn about $11 or $12 million, good for fifth place.

Top five predictions:
1. 'The Expendables,' $30.7 million
2. 'Eat Pray Love,' $24.7 million
3. 'The Other Guys,' $18.4 million
4. 'Scott Pilgrim vs. the World,' $17.5 million
5. 'Inception,' $11.8 million

•Follow Gary Susman on Twitter @garysusman.