On one hand, you have one of the greatest dramas in the history of film. A movie that, (according to the film "You've Got Mail" and quite accurately) can explain EVERYTHING in life at one time or another. Some of the greatest characters of all time, and one of the most riveting descents of a character from wholesome good guy to despicable heel.
On the other hand, you have one of the best farce films ever made in MPHG. The British Comedy Troupe's most famous work (some argue Life With Brian was a better film), Monty Python has to be in the top 20 list of the most quotable films every made.
But it's no where NEAR The Godfather. Coppola's classic has, and forever will, stand the test of time. An author wrote two books - The Godfather Returns and The Godfather's Revenge to explain what happens between the first the second films, and the second and third films. Maybe we will see them become films one day, akin to Star Wars. Maybe Scorcese will direct them. Or maybe they will just leave the legacy alone.