No. 5: Iron Man
It’s possible Iron Man won’t ever slip from the Top 5. Despite being the first film in the MCU, it still holds up amazingly well. The bulk of the credit goes to Robert Downey Jr’s perfect casting as the self-obsessed billionaire who learns to become a hero.
Director Jon Favreau knew exactly how to approach the character in a way that didn’t diminish what made him special. The armor looked like it came from the comics and Tony Stark was just as entertaining as Iron Man. Those were vitally important elements beyond big time action and the right balance of humor. Iron Man set the bar high for the other Marvel films and all these years later, it still remains a standard bearer for the brand with just a few exceptions.