In fact, I saw it twice. And I tried to hold off on a discussion entry as long as I could. Because--here's the thing. There really isn't a ~MIND-BLOWING TWIST~ that shows up halfway through or anything. There's no one thing I can really tell you, like with The Sixth Sense or The Matrix, that would just spoil the entire concept of the movie. Which is why it's so much more rewarding to go in and let the movie unfold itself for you. Not because there's any one big thing that's supposed to CHANGE THE WORLD, but because spoiling yourself would rob you of a hundred little moments of "Holy shit, that was badass." You know. Like with a lot of really good movies. It's probably the best movie I've seen this year, but... that's not a real tall hurdle to clear, to be honest with you. Like, the second best was probably Shutter Island, and the third best, unless I saw something better and I'm just not remembering it, was probably... Eclipse. Yeah. It's been that bad.
(Wait, no--I technically saw Sherlock Holmes on January 1st. There you are.)
ETA: I should add: the discussion above sounds confusing because I'm leaving a lot of stuff out. It sounds more cryptic than it is. In fact, I thought Inception was remarkably straightfoward, considering, and this is in large part due to really good editing, I think. I had no problem following it on a first viewing, aside from that one point that got discussed on Twitter, and it's a lot more accessible than it sounds.