So far, these come to mind:
Edit: Now with current rankings.
- (1) 12 Angry Men (I listed it first by chance, but it may be the best.)
 - (2) To Kill A Mockingbird (But, man, the prosecutor was horrible.)
 - (5) A Time To Kill (The only Grisham film worthy)
 - (3) My Cousin Vinny (more realistic than you think)
 - (4) The Paper Chase (great law school movie)
 - (6A) Jagged Edge (underrated)
 - (10) Witness for the Prosecution (oldie but a goodie)
 - Anatomy of a Murder (ditto)(And, I admit, it's been a long time since I've seen it and might under value it.)
 - (7) The People vs. Larry Flynt (Has the greatest line ever when the defense lawyer is simply fed up with him but Flynt replies with: "You don't want to quit me, I'm your dream client: I'm the most fun, I'm rich, and I'm always in trouble."
 - A Few Good Men (overrated)
 - (9) Philadelphia (better when you watch it now)
 - (10) Devil's Advocate (Pacino's performance alone makes it worthy of the list)
 - (6) Presumed Innocent (Still confusing to me but very realistic if you want to know how a DA's office works, the pressure of being a defense lawyer and, more importantly, the pressure of being accused.)
 - (9) The Verdict (A great movie on legal ethics.)
 - Edit: Cape Fear. (This was nominated by a reader and I wanted to dismiss it because it wasn't a "legal" movie. But the more I think about it, it is exactly that. )
 - Edit: Fracture (Something about it just bugged me. I can't put my finger on it, though)
 - Edit: (8A) Primal Fear (I'm thinking it might go higher)
 - Edit: Suspect
 - Edit: Murder in the First
 - Edit: Sleepers
 - Edit: JFK
 - Edit: Kramer vs. Kramer
 
Edit: Nominated by readers but which I have not seen:
- Justice For All
 - Body Heat
 - Lincoln Lawyer (my bad for not seeing this)
 - Absence of Malice
 - Inherit The Wind (how have not seen this?)
 - Judgment at Nuremberg
 - Class Action
 - Ghosts of Mississppi
 - Life of David Gale
 
- Legal Eagles
 - Legally Blonde
 - The Firm
 - The Juror
 - The Rainmaker
 - The Pelican Brief
 - Runaway Jury (as you can tell, I don't think much of John Grisham movies because I don't think he ever spent time in the courtroom.)
 - Liar, Liar