Hands down, "Inception" turned me into a huge admirer of Christopher Nolan's work, and I wanted to watch everything that came beforehand, e.g., "Memento", and everything afterwards, especially "Oppenheimer."
The cast was top-shelf. Besides DiCaprio, Tom Hardy, Cillian Murphy, Ken Watanabe, and Joseph Gordon-Levitt to name a few. The special effects were absolutely incredible, and I agree with Rooster Ties, the premise was borderline insane, and the action scenes were ridiculously good! I also really liked Hans Zimmer's soundtrack too, as it really added a feeling that something ominous was always about to happen at anytime.
Just an overall excellent movie, one of my favorites from the last 15-20 years.