Dark Knight is more of an event than a movie. It's big and bold, wide and deep. The performances are larger than life yet fully human and extremely stirring. The special effects and new toys are simply dazzling.
The plot unfolds in somewhat of a puzzle that eventually comes together. I found the character & dialogue of The Joker to be one of the finest metaphors for the implacable, sociopathic enemy we face in the real world, in the War on Terror. Pay special attention to Michael Caine's brief but stunning appearances.
Likewise, I found the portrait of Batman and his small band of loyal allies to be an accurate and haunting metaphor for President Bush -- the hero we don't deserve, but the hero that we need... the hero who doesn't flinch regardless how many people abandon the mission.
But over and above everything, Dark Knight is HUGELY entertaining. It is so rare these days to feel like you got an excellent product from Hollywood. Too often Hollywood only gives normal earthlings a slap in the face for their hard earned money. I am very pleased for Heath Ledger that Dark Knight will add a big gold star to his legacy. He gave a very disturbing, unforgettable performance.
To be honest I cannot wait to pay more money to see Dark Knight a second, and maybe a third time. I don't think I was able to absorb it all in one sitting.