Well for a start Sean Astin saves the world in LOTR, sooky boy Elijah would have stuffed us all without good ol’ Sam, because Frodo would have spat the dummy. If you check out IMDB he is not even listed in the cast until you select more. Entirely appropriate.
I gotta say Harrison Ford. Not only did he stop the Nazis from world domination in Raiders, he also saved the whole galaxy in Star Wars (does that count?) Surely something he did in the Jack Ryan movies saved the world at some level.
Plus, I think he saved us all when he didn’t make a sequel to Regarding Henry…
Richard Dean Anderson–as Colonel/General Jack O’Neill of Stargate SG-1, as MacGyver, and possibly as the pilot in “Pandora’s Clock” (haven’t seen it)–might be a contender. Of course, the rest of SG-1 deserves a big chunk of the credit for most of the saves in that show; still, he was the key to it on several occasions.
I have to disagree. Absolutely nothing Indy did in that movie made an absolute bit of difference, other than the fact that he actually led the Nazis to the ark. The ark itself did the dirty work while Indy was tied to a post.
How about Will Smith? Independence Day, Men In Black, Wild Wild West? I, Robot?