15 minutes before watching this film, I didn't even know it existed.  But damn, Nolan did a knock-up job with this.  The story and mystery of Memento is excellent, and it's one of the most unique mysterys I've ever witnessed.  Unfortunately this movie is slightly bland in all other departments, boasting average visuals, acting, and characters (except Leonard he's pretty good).  This doesn't matter too much during the movie, as I was so invested in the mystery that I could care less about most other things.  After it was all over, I was satisfied, yet I still thought about the story hours after I had finished it.  This is a great film, and based on the fact that I had never heard of it before, a very underrated Christopher Nolan film.