Actors who play roles others have undertaken risk comparison to their predecessors. There will always be arguments over who is the best James Bond (it's predictable, but I like Sean Connery the most) or the best Dracula (Bela Lugosi and his accent are legendary but Christopher Lee was a better, less hammy actor and Gary Oldman conveyed world-weariness well), among many others.
The Joker in the Batman movies is another character where people can choose a favourite big-screen portrayal. Whatever their relative merits, each actor managed to create something distinctive about the twisted character: despite having to make the character recognisable, no two portrayals looked or sounded the same.
In the latest entry in the DC film universe, Joaquin Phoenix's performance as the title character in Joker has deservedly won much acclaim. In this film - leaving aside interpretations of what the ending might mean - the Joker begins as downtrodden Arthur Fleck.
He's a party clown and would-be stand-up comedian with a neurological disorder that makes him laugh involuntarily. (Phoenix does a good series of laughs - involuntary, insane and perhaps even real).
Arthur lives unhappily with his invalid mother and struggles through life until he snaps mentally, puts on the makeup full-time and lashes out violently against a world that ignores and abuses him. It's a vivid performance by someone you might not associate with such a role.
But if you're looking for a Joker with humour to go with the insanity, this isn't it: this Joker is scary and sad but not at all funny. Phoenix is not, of course, the first actor to play the Joker.
There are prerequisites for the character - a white face, green hair, grin, manic laugh - but the Joker can stand multiple interpretations, from the gleefully goofy to the seriously disturbed. Here, we'll just consider the major big-screen movie portrayals.
Cesar Romero in the 1960s Batman series and its film spin-off was over-the-top and most comedic (seeing his moustache - he refused to shave it off - under the white makeup added to the bizarre quality). But Romero's Joker could still be unsettling, especially with his manic cackle His look - white face, red mouth, green hair, purple suit - from the comics carried over into most of his successors.
Jack Nicholson in the Tim Burton movie was, well, Jack the Joker, but he's a brilliant star who can naturally convey leering menace so it worked. Jared Leto's manic take was not especially memorable but a little better than the underwhelming Suicide Squad deserved.
Still, it pales in comparison to Heath Ledger's disturbed - and disturbing - figure in The Dark Knight. Leaving aside the initial doubts at his casting and all the talk after his far-too-early death, it's an excellent performance (that won him a deserved posthumous supporting-actor Oscar).
Zach Galifinakis brought a needy, childish side to the Joker and his symbiotic relationship to Batman in his voice-only The Lego Batman Movie while Mark Hamill's vocal performance in Batman: The Killing Joke ranged from cultivated to crude to crazy.
We won't go into who's been the best Bruce Wayne/Batman: he always seems stiff next to Joker, no matter who's playing him or how edgy he's meant to be.