While not the popular opinion, the theatrical version of Superman II (credited to Richard Lester) remains my favourite Superman movie to date. While the Richard Donner cut of the film has some standout moments (particularly the inclusion of Marlin Brando returning as Jor-El), it also leaves some of my favourite moments from the theatrical version.
Superman II was also the first superhero movie I ever saw, and so for that it remains one of my favourites to date. Terence Stamp still stands as one of the best villains in comic book movie history and in my opinion the film features Christopher Reeve's best performance as the Man of Steel. While there are some silly comedic moments in the film, the strengths clearly outweigh the weaknesses and I feel it will be incredibly difficult for any future Superman films to top this entry.