Film/TV castings that nearly happened - but didn't

[TheGospelAccordingToMe]

I'm just reading an article about the new Trainspotting musical (nope) and apparently Danny Boyle wanted Christopher Ecclestone to play Begbie in the film. Ecclestone turned it down because he wanted to play Renton! I can't imagine him in either role and the film was perfect without him.
On the subject of Danny Boyle, Ewan McGregor was supposed to play Richard in The Beach but it went to Leonard DiCaprio to appeal to the American audience. Totally miscast. Ewan McGregor would have been so much better and he didn't speak to Boyle for ages because of it apparently.
Does anyone know of any other film/TV castings that would have been better or worse had the original choice been cast?

Very well known but Lisa Kudrow was originally cast as Ros in Frasier. I think the character wouldn’t have had the same strength at all with her. Though if she’d been kept, perhaps they wouldn’t have felt the need to have Jane Reeves being unpleasantly whimsical as Daphne - Lisa could have done a more acerbic version.

David Jason was almost cast as Corporal Jones in Dad’s Army but lost out to Clive Dunn.

Charisma Carpenter was almost cast as Buffy, or Sarah Michelle Gellar as Cordelia, but I can never remember which way round it was!

When I was much much younger, I worked on StarWars episode 2 for a bit and saw promo shots with Leo DiCaprio as Anekin

I believe Hugh Laurie auditioned for Rimmer in Red Dwarf, which I could totally get behind, although Chris Barrie also fantastic. When I Googled to check, the internet also tells me Alan Rickman was in contention for the same.role, which I actually can't imagine!

Billy Idol was meant to be the bad Terminator in Terminator 2 (presumably complete with a lip curl)!

Paul McGann actually started filming Sharpe.

Not TV but 'Back tot he Future' originally had Eric Stoltz playing Marty, again they started filming.

Russell Brand was in the running to play SuperHans in Peep Show. Thank God that didn’t happen because a) it would have been fucking terrible and b) Peep Show would basically have ended up cancelled.

Tom Selleck was almost cast as Indiana Jones but couldn’t take the role due to his obligations on Magnum P.I. Also Betty White and Rue McClanahan were supposed to play each others roles in The Golden Girls but switched.

Jim Broadbent was offered the part of Del Boy in Only Fools and Horses, but he was unavailable due to other commitments, so David Jason got the part. I can't imagine anyone other than David Jason playing Del, and Jim Broadbent went on to a hugely successful career in TV and film- he played Roy Slater in Fools and I thought he played that part really well!

Tamzin Merchant was originally cast as Daenerys Targaryen in Game of Thrones. I can’t imagine anyone other than Emilia Clarke in that role.

Nicholas Cage was very nearly Superman.

Colin Firth originally turned down the role of Mr Darcy in Pride and Prejudice 1995 - he had never read the book and didn't see himself as a romantic lead (IIRC his actor brother mocked it by saying to him "isn't Darcy meant to be sexy?")

However the team talked him into it and the rest is history