I have mixed feelings about the claims that Heath Ledger only won this Oscar because of his death. In one sense I feel that's wrong, as it was a brilliant, unforgettable performance that was more than worthy of award recognition. But regardless of how great or deserving a performance it was, just look at how The Dark Knight - thoroughly deserving of major award nominations itself - was pointedly snubbed elsewhere in the ceremony...
But that's all conjecture. The key point is that Heath Ledger won, and the win is well deserved. Congratulations, Heath, and thank you for bringing the ultimate Joker to the big screen.