He was EXCELLENT as Anakin in Episode 3. He managed to make a pretty boy SCARY. Probably his best moment was how he acted with his face after Grievous killed Padme; you could totally believe his hate and his anger. All in all, he did a great job bringing Darth Vader to life. I think his portrayal of Anakin also made it much easier for Nolan to justify casting him as the Joker in the Dark Knight. If he hadn't already proven himself, we may have seen someone like Hayden Christensen or something as the Joker, and imagine how much that would have sucked! Instead, Ledger's Joker has been one of the most consistently present villains in the DCCU, and I wouldn't have it any other way.