Bill Murray as Batman
It is considered folklore, but back when it was a big deal: Michael Keaton being cast as Bruce Wayne in Tim Burton's Batman caused such outrage among comic book fans, that 50,000 protest letters were sent to Warner Bros. The studio may have gotten 100,000 if Bill Murray had filled the role, as was a strong possibility for some time. It was all a symptom of the mixed-up mid-'80s, about the time when someone thought it would be a good idea to have Richard Pryor play a super-villain (in Superman III).
The Murray Batman was going to be similar in style to the campy Adam West TV show of the '60s, but the project was eventually met with a big "Kapow!" and Warner Bros. made the right choice in hiring Tim Burton, fresh from the surprise success of Pee-Wee's Big Adventure and Beetlejuice, who took the film in a completely different direction - towards box-office gold.
Every man and his dog was said to be in the running for the role of Burton's Billionaire with the bat fetish - most notably Mel Gibson and Alec Baldwin - but Keaton won out, and won over the fans with his dark and disturbed portrayal of the victimized vigilante. Murray himself was glowing in his praise of Keaton.
“I would have been a fine Batman. You know, there have been a number of Batmen. I like them ... I thought Mike Keaton did a great job as Batman. It's obviously... it's a great role."
Jake Gyllenhaal as Batman
Speaking of dark and disturbed, Jake Gyllenhaal had played just that as the title character in cult-hit Donnie Darko. He was looking for an upgrade when he tried for the prize part of Bruce Wayne in Christopher Nolan's Batman reboot, Batman Begins. He was said to be writer David S. Goyer's first choice before screen-testing.
Gyllenhaal was one of the final eight actors to audition for the part, the others being Canadian Joshua Jackson, fellow Americans Eion Bailey and Billy Crudup, along with European actors Cillian Murphy, Henry Cavill, Hugh Dancy and Christian Bale, who Nolan pushed for and got, despite the actor being a real-life stick figure after appearing in The Machinist.
While Bale got the spoils, Murphy impressed Nolan so much he cast him as Dr Jonathan Crane, aka The Scarecrow. The closest that runner-up Gyllenhaal got to being involved in a Batman movie was having his sister Maggie star in The Dark Knight. Jake Gyllenhaal was apparently in talks to play DA Harvey 'Two-Face' Dent in that sequel, but was again overlooked, this time for Aaron Eckhart - thankfully.
While he has matured in the years since trying out for Batman Begins, and has packed on considerable muscle for the upcoming The Prince of Persia, back then Jake Gyllenhaal was certainly more suited to a Peter Parker/Spider-Man-type superhero. Of course, he just missed out there too after Tobey Maguire was able to recover from a back injury just before filming Spider-Man 2.