How do you think the story would have been different if Gandalf had not fallen at the Bridge of Khazad-Dum?
For one thing, I don't think that Boromir would have died. Gandalf would have been there to prevent Frodo from leaving and Boromir from dying. But, then he wouldn't have become the White Wizard, and he, Aragorn, Legolas, and Gimli wouldn't have been at Helm's Deep. He probably would have been with Frodo, which would have changed that whole aspect of the story. And Aragorn might have gone with Boromir to Minas Tirith and then Denethor might not have gone crazy and... Whew! There's a lot. So I guess that Gandalf falling was important to how the story turned out.
What do you guys think?