4. Nikolaj Coster-Waldau
See above: a toothy smirk that says, "I know something you don't... And that thing is detrimental to your well-being". Or words to that effect. Nikolaj Coster-Waldau might only have gained international recognition for his role as Kingslayer Jaime Lannister in HBO's Game of Thrones, but his career in his native Denmark dates back to 1994. With his flowing blonde tresses - the Lannisters are, after all, the house of the lion - and high cheekbones, there's a touch of Heath Ledger to him (more so than any of the other actors on this list), though at 43 he's ten years older than Ledger would be today. Though his Danish filmography features a surprising lack of morally ambiguous crime dramas - the country's staple export these last few years - his role as a high-profile businessman and would-be assassin in Headhunters, a Norwegian adaptation of Jo Nesbo's book, has shown a more relentlessly threatening side to his persona. In both roles - as Jaime Lannister and executive Clas Greve - Nikolaj (I'll refer to him by his first name to avoid having to repeat the double-barreled surname) is smooth, urbane, and deeply violent: he'll beguile you with a story then beat you death with his chains. A more physically dangerous Joker, such as appeared in Death in The Family or perhaps Dennis O'Neil's standalone series, would certainly him from Ledger's iconic interpretation (hardly a pacifist but more inclined to wrought his chaos at a distance). Snyder's 'verse is "naturalistic" in its presentation than Nolan's, but also more fantastical - accounting for the presence of Superman. As such, if DC are looking for a vehicle for a more outlandish, even cartoonish Joker, then Nikolaj could be the perfect vehicle for the character: stump-clutching, sister-bedding, smeared in bed, he's already proven he's willing to take on the less glamorous elements of characterization. Let's see how far he's willing to go. However, with GoT's shooting schedule it's unlikely that, even given the multi-layered nature of the piece, the many, many character arcs, etc., that he could find time to balance his role in it with the commitments required by even a supporting villain. Ledger buried himself in The Joker for months in order to find his take on the character - it may or may not have contributed to his state of mind at the time of his death - and, even if Snyder and Co. are looking for a more by-the-book take on Batman's nemesis - a threat but not a feature - this isn't going to be a quick, cash-the-pay-check job. There are many other actors who could inhabit the part just as well (at least nine of them, in fact), so for now we'll most likely have to be content on watching Nikolaj Coster-Waldau as an enthralling component of Game of Thrones week in week out. *sigh*