Review in a Hurry: It's tough to review a movie when everyone you mention the title to sticks their fingers in their ears and goes "LALALALA! No spoilers!" So all we'll say to those folks is that Inception's a smartly scripted, big-budget action/heist movie of the sort you'd expect from the director of The Dark Knight.
If that's not enough for you, keep reading, and we'll go easy on spoilers:
The Bigger Picture: Though there will undoubtedly be (valid) comparisons made to The Matrix and Solaris, a more blatant antecedent for Inception is Joseph Ruben's 1984 thriller Dreamscape, in which Dennis Quaid must enter the President's nightmares to prevent an assassin from doing likewise. Here, the rules are more complicated, but the basic idea is the same—infiltrate a dream in order to effect (or prevent) global change.
In this case, the man whose subconscious is to be plumbed is wealthy heir Robert Fischer (Cillian Murphy), whose name-resemblance to a certain famous chess player is surely no coincidence. While the team members assembled for the job by master dream-weaver Cobb (Leonardo DiCaprio) are generally expert at finding secrets within the mind, the trick here is to pull off the far more delicate trick of inception. Planting an idea so deeply and cleverly into Fischer's subconscious that he believes it to be his own.
What is important is that Cobb brings his own subconscious baggage, which threatens to influence the dream reality in unintended, detrimental ways. And unlike in Dreamscape or the Freddy Krueger movies, dying in the dream doesn't mean death in reality, but it can mean that your mind takes a trip into a devastating limbo from which it may never return.
Other aspects of dream logic prove equally novel here, particularly regarding the passage of time in dreams, and the way external stimuli influence the gravity of the situation, literally and figuratively. (Those twisty-floaty corridor fights you saw in the trailer are every bit as awesome as promised.)
It's also instructive to note that director Christopher Nolan makes far more effective use of DiCaprio as a man with a dark secret than Martin Scorsese did in Shutter Island, or ever.
Amid an all-star cast that also includes Ken Watanabe, Marion Cotillard, Ellen Page, Joseph Gordon-Levitt, Michael Caine, and Tom Berenger, it's the less-known Tom Hardy (Bronson) who steals the show, as the one guy who seems to know more about inception than Cobb. (He may not have been the best Star Trek villain ever, but he'll make a fine Mad Max.)
Nolan's script, meanwhile, is smart enough—without being impenetrable—that it gives you hope for any possible Batman sequel involving the Riddler. And Hans Zimmer's score may give you chills.
The 180—a Second Opinion: One of the main dreams involves an arctic setting resembling a Metal Gear Solid game, and sees every character covered head-to-toe in identical white outfits. This can at times get as infuriating to follow as the blurry, brown fight scenes in Batman Begins.