In fact, it's too difficult for me to give a definitive answer!
I could talk about the several standouts, but then this post would turn into a long yawn instead of a reply; I would prefer to be more brief and coherent...
Reading what everyone else had to say, I found myself nodding and saying, "Yeah, uh-huh... yup! That was an excellent moment!"
There were so many dramatic moments in all three movies that it is simply beyond my ability to nail down just one scene that I particularly enjoyed as being the best of them all. I'm glad to see that I am not the only person to express this sentiment!
This is a GREAT bulletin board!
Okay, I will mention one scene, because I found it to be amusing, romantic, and very heartwarming...
I loved the scene that takes place during Michael's courtship of Appolonia, and they're out for a stroll... with a gaggle of chaperones trailing behind them... with Franco Citti and the traitor Fabrizio bringing up the rear.