With the media hype machine for Iron Man kicking into overdrive, it's easy to forget that 43-year-old Robert Downey Jr. wasn't always destined to play billionaire turned superhero Tony Stark. During its long, long development journey, the Universal, then Fox, then New Line, and now Paramount production has notoriously chewed up and spat out actors, not to mention A-list writers and directors (Joss Whedon and Quentin Tarantino top the list of approached contenders). Whether you love or hate RDJ as Iron Man, it's worth taking a look back at the Iron Men who never got to strap on the suit. —Michelle Kung

Nicolas Cage (1997)
Backstory: After Fox rescued the film from years of development hell at Universal, Cage eventually backed out of the project because of a previous commitment to play Superman in the ultimately doomed Superman Lives. Oops.
Stark value: If Cage's intense portrayal of an arms dealer in Lord of War is any indication, his Stark would have been a far more morose SOB. And the less said about Ghost Rider the better.
Total Starkness:

Tom Cruise (1998)
Backstory: After Cage exited, Cruise threw his iron helmet into the ring but was waylaid by Marvel's bankruptcy/financial issues. He flirted with the role before finally nixing it in 2005, explaining, "It just didn't feel to me like it was going to work."
Stark value: Cruise must be kicking himself now; in short order Robert Downey Jr. might be a bigger star. His cocky intensity might have made him a nice fit in the iron suit.
Total Starkness:

Leonardo DiCaprio (2003)
Backstory: Although the Departed star was never approached (as far as we know), producer Avi Arad claimed DiCaprio was at the top of his short list of candidates.
Stark value: Given that he scored an Oscar nom for portraying another eccentric, yet dashing, billionaire in The Aviator, we think he could have played a great Tony Stark. Bonus: past experience with playing men in Iron Masks.
Total Starkness:

Justin Timberlake (2004)
Backstory: After Nick Cassavetes (The Notebook) was brought on to direct, rumors circulated that he was interested in casting his Alpha Dog star as Stark.
Stark value: Iron Boy, not Iron Man.
Total Starkness:

Rob Lowe (2004)
Backstory: Fanboy Websites reported the Brothers & Sisters star was being tossed around as a possible star among producers, a notion that was quickly dismissed.
Stark value: With his chiseled good looks and senatorial demeanor, Lowe has the billionaire playboy part down pat — but can you really see him kicking anyone's ass?
Total Starkness: