1. Devil's Advocate
    Pacino as the senior partner who is also the devil?
  2. My Cousin Vinny
    The two youts! Also illustrates limits of interrogation testimony ("I shot the sheriff." vs "I shot the sheriff?!?!")
  3. A Few Good Men
    Probably the best courtroom confession on film
  4. The Social Network
    It's basically all depositions
  5. The Fugitive
    More about law enforcement than the law, per se, but touches on themes of wrongful conviction and rules vs justice.
  6. Michael Clayton
    Big Law in a nutshell.
  7. To Kill A Mockingbird
    Yes, it's about a lot of things, but the law is featured quite prominently.
    Suggested by @Larry