BEVERLY HILLS, California — To be a movie fan is to know the almosts and know them well. Christopher Walken auditioned for the role of Han Solo; Eddie Murphy passed up a chance to be in "Ghostbusters"; Mark Wahlberg and Joaquin Phoenix came thisclose to sharing a hike up "Brokeback Mountain."

Surf around the Net, and you'll uncover so many castings that fell apart for one reason or another. But even if you ended up loving the final product, it's tempting to wonder if moviegoers in some alternate universe are watching those movies — and if so, what exactly are they watching?

"Oh my God, yes," veteran director Jon Turtletaub responded when asked whether he still thought twice about some of his casting near-misses. "But it's weird. You don't want to talk about them, because you don't want to talk about mistakes."

Sometimes they are mistakes — and sometimes, the movies are better off having switched actors, directors or writers a half-dozen times. There might not be a more obvious example of the latter than [article id="1531438"]Will Smith's turn in the flick "I Am Legend."[/article] Long-considered one of Hollywood's greatest unmade films, there's little doubt that the film found its perfect star.

"It was, what, '94 that Warner Brothers took it in," Smith remembered of the project, based on the classic 1954 sci-fi novel of the same name and already filmed as 1964's "The Last Man on Earth" (with Vincent Price) and 1971's "The Omega Man" (with Charlton Heston). "It definitely has evolved with the times."

What audiences might not know as they fork over their $10 to see "Legend" this month is that the script spent two decades passing through the fingers of directors like Michael Bay ("Transformers") and Ridley Scott ("American Gangster"), and being attached to such leading men as Michael Douglas and Tom Cruise. Most shocking of all, perhaps, is that "Legend" spent most of the '90s as the constant, near-mythical project constantly being hyped as Arnold Schwarzenegger's comeback vehicle.

"Those earlier versions were not emotional versions," explained "Constantine" director Francis Lawrence, who took on the futuristic story of an immune man battling diseased "dark-seekers" after his peers had thrown up their hands in frustration. "[The previous scripts] were much more action-oriented, much more shooting of guns, much more testosterone."

So after all these years, why is "I Am Legend" finally coming to a theater near you? Because it's one of the rare scripts that has evolved with the times.

"I think that the time where you could just blow some stuff up and expect people to come to your movie, that's over," Smith said. "The audiences are more savvy; people are going frame-by-frame on their DVDs and computers right now. They see everything that you do. The audience is much more cinema-savvy than ever."

With such Hollywood savvy in mind, we couldn't help but solicit more "almost" stories from the stars themselves. And some of their revelations are certainly the stuff of "Legend."

"There was a couple of movies that I was offered, but I had good reasons I couldn't do them," Nicolas Cage said. "One was 'The Matrix,' and then 'The Lord of the Rings.' "

In the former, Cage would have played Keanu Reeves' character of Neo; in the latter, Cage revealed that he would have been Aragorn, "but I thought what Viggo [Mortensen] did was terrific. ... Both are great movies, but they both shot for great quantities of time — I mean years. Australia was 'The Matrix,' and New Zealand was 'The Lord of the Rings.' I had family obligations, so I'm glad I stayed and had those experiences with my family."

As recently as a few years ago, "My Name Is Earl" star Jason Lee made news with [article id="1459549"]rumors he would star in a remake of the comedy classic "Fletch."[/article] According to the star, the project came close to fruition before falling apart. "That would've been fun, and I would have been working with Mr. Kevin Smith again," he sighed. "But it didn't happen. ... I think that may have died — and maybe that's a good thing that it may have died with Mr. Chevy Chase."

Another near-casting that fell apart? Jack Black's rumored Green Lantern movie. "The bastards!" Jack Black laughed. "I really liked the script that a friend of mine wrote, but nobody wanted to make it. It was too weird. ... It would have been a comedy, and they didn't want to go that way with the character. ... Batman, Superman, Spider-Man — they're all pretty straight-up."

Actors aren't the only ones who find an "almost-casting" hard to forget. "I'm the guy who turned down Angelina Jolie for a part," laughed Turtletaub, remembering his 1999 drama "Instinct" with Anthony Hopkins and Maura Tierney. "Ha-ha, idiot!"

"Take 'While You Were Sleeping,' a romantic comedy with Sandra Bullock and Bill Pullman," Turtletaub continued. "Demi Moore wanted to do that movie, and Nicole Kidman wanted to do that movie, but the schedules didn't work out, so we ended up settling for Sandra Bullock ... We had two actors auditioning [for the Pullman role] who had accents that didn't really sound like Chicago, and they were unknowns: Matt McConaughey and Russell Crowe.

"But when your movie comes out, you can't imagine anyone else in that movie," he finished. "So you sit there and you go, 'OK, it worked out.' "

"They offered me Snape, which is now ably being done by Alan Rickman," remembered "Reservoir Dogs" star Tim Roth of the "Harry Potter" gig he turned down. "I was going to do both ['Potter' and 'Planet of the Apes']; we rigged it so that I could fly back and forth. They figured out the schedule, but it just got to be overwhelming. ... I would have made [Severus Snape] a very different guy."

Even Will Smith has had plenty of missed opportunities — so he doesn't feel quite so bad about stealing "Legend" from the Governator. "I don't know if you remember 'K-PAX,' " he asked, referring to the 2001 drama that would eventually star Kevin Spacey. "I loved, loved, loved [the script for] 'K-PAX,' but it never really jelled in my mind. I always wanted to make that movie.

"There was also 'Phone Booth,' " Smith added, remembering the 2002 Colin Farrell flick. "I loved 'Phone Booth,' [but I passed because] I always felt like the bad guy's story wasn't clear enough."

Ultimately, "Phone Booth" became another long-gestating flick that also went through the hands of Tom Cruise. But as "I Am Legend" mixes blood and brains into its rare blockbuster mix, audiences are likely to be pleased that, for once, it was Smith who was the last man standing — and now he's the last man on Earth.

Check out everything we've got on "I Am Legend."

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