1. The Joker/The Riddler - Tim Burton's Batman Franchise
Lets face it, Batmans rogues gallery are, to a man (and occasionally woman), disturbed and psychotic freaks and ghouls, as befits a terrifying, crime-obsessed gothic city like Gotham, whose Arkham Asylum must contain half the town by now. Robin Williams had been after a part on a Batman movie since they started thinking about making Batman movies again in the late 1980s. Towards the end of his life, it had become almost a running gag in interviews that he was still in the running to play either the Joker or the Riddler, or anyone else in the Batman mythos. Movie scuttlebutt has it that Williams was up for consideration in Tim Burtons 1989 version of the story, before Jack Nicholson once again skated past him to secure the role yet another that would become synonymous with him, although its easy to imagine the spin that Williams would have put upon it Jack Napier. The same was true of the Riddler in Joel Schumachers Batman Forever. At one point, Williams was actually offered the role, but allegedly took his time signing the contract, and lost the role to Jim Carrey. The Joker came up again when Christopher Nolan set about rebooting the Batman Franchise, and Williams was considered once more, having worked with Nolan to great effect as the villain in his previous movie Insomnia. Of course, its difficult to imagine anyone other than Heath Ledger in the role now, but its likely that, with the Batman franchise rebooting once more, Williams was being considered for an older Joker once again perhaps one more in the vein of the characters portrayal in Frank Millers seminal Dark Knight Returns. Now that would have been interesting