Michael Myers. Darth Vader. Hannibal Lecter. Alex De Large. Lex Luthor.

What do these cinematic villains have in common?

They pale in comparison to the late Heath Ledger's terrifying portrayal of the Joker in "The Dark Knight."

Every once in a while an actor will emerge and completely steal the show, capturing each scene he is in (i.e. Peter O'Toole in "Lawrence of Arabia").

And in case you missed it -though judging by the opening weekend box office record of $158.41 million for "Knight" you didn't - Ledger does just that.

After all, any actor who can go from playing a gay cowboy ("Brokeback Mountain") to arguably one of the most sadistic villains on the big screen has plenty of range.

Ledger, who died of an accidental prescription overdose on Jan. 22 at the age of 28, gives perhaps his finest performance as the cackling, sadistic Joker in "Knight." But it's hard to believe that his death had nothing to do with his immersion in the role, no matter what the makers of "Knight" claim.

Like all of his roles, Ledger gave everything, yet this particular role was different. His sleep, or rather lack of it, was becoming a problem. For example, toward the end of filming "Knight," Ledger was quoted as saying he "probably slept an average of two hours a night" and that he "couldn't stop thinking."

As the Joker, how could one possibly think of rest? Unfortunately, the Australian-born Ledger had so much potential; his work is best exemplified in "Knight."

My obsession with this insane clown character didn't peak until finding out Ledger was cast in July 2006. At the time, the question that immediately came to mind - as it did with many others - was why him?

Of course, this changed last week, especially when Joker growls "let's put a smile on that face" before doing away with a thug. His smeared clown make-up concealing his scars to his realistic mannerisms (i.e. nervous facial tic) also make Ledger's performance that much creepier.

His background pertaining to how he got the scars on his face is chilling; though it isn't shown, the explanation he gives is riveting and utterly terrifying.

Without giving too much away - for the few remaining who haven't seen "Knight" - Joker's introduction during a bank robbery is genius, and quite possibly the best opening of a film I've ever seen. What the Joker does with a pencil in the next scene is captivating, and Ledger's chemistry with Christian Bale (Batman) is spot-on during a scene in the interrogation room.

Since "Knight" premiered nationwide Thursday, I've already seen it twice. But the first time - which came at 12:01 a.m. on opening night at the IMAX, along with hundreds dressed as the Caped Crusader and Clown Prince of Crime - was indescribable. Especially the walk to the car at 3 a.m., fully aware that Ledger is gone.

But his legacy will live on, and thanks to "Knight" it should put a smile on plenty of faces.

What you should know:

Believe the hype. Arguably, this was one of the finest performances ever given on-screen by a supporting actor in a major action film. Without question, Ledger will earn a posthumous Oscar nomination. And it shouldn't come as a surprise if he actually wins it, either.

What you need to know:

The 2008 version of the Clown Prince of Crime is nothing like Jack Nicholson's Joker in 1989's "Batman." Ledger's take makes Nicholson's version look like Bozo the Clown. Nor is it like Cesar Romero's version in the 1960s television show, "Batman." No, think deeper and darker - much, much darker.

What you probably didn't know:

According to Wikipedia, before Ledger was cast as the Joker, several actors publicly expressed interest in the role, including Steve Carell, Adrien Brody, Paul Bettany and Robin Williams. And now rumor has it that Johnny Depp might be the Riddler in the next Batman installment.