With his blond but bluntly masculine good looks, Heath Ledger - who has been found dead in his New York apartment aged 28 - was made for himbo roles. He embraced them, but wanted more. He shuttled between generic and prestige projects, suffering successes and failures in both camps. Sporadically, he showed us what a fine actor he might be.

Early on, Australian Ledger did the obligatory soap stint in Home and Away. Long before he played a gay cowboy in Brokeback Mountain, he played a gay cyclist rather than a straight swimmer in the Aussie athlete drama series Sweat, believing it the more interesting role. His first years in Hollywood showcased his versatility. He was as charming as a young Cary Grant in 10 Things I Hate About You and a nostril-flaring son to Mel Gibson in The Patriot. His larrikin charm made A Knight's Tale a cult hit.

Was it his fault, or the film-makers', that Ned Kelly, The Four Feathers, and Casanova didn't make him a bona fide star? A bit of both. He lacked the charisma of Gibson, and didn't choose his blockbusters well. But by now Ledger was focused on proving his acting chops, and Brokeback Mountain was a happy occurrence. He was perfectly cast  -  not because he was a better actor than co-star Jake Gyllenhall, but because he was more butch and more authentically conflicted.

Ledger then seemed to seek out darker, angrier supporting roles. In Todd Haynes's I'm Not There, he is by far the most aggressive and brooding of the six Bob Dylans. Two weeks ago I saw startling footage of the forthcoming Batman, in which Ledger's twisted, ugly Joker blows away the cartoonish memories of Cesar Romero and Jack Nicholson. It might prove to be the best, as well as his last, performance.