In The Seventies, Stan Lee penned a Spider-Mancomic involving narcotics portrayed in a completely negative light, on the recommendation of the United States Department of Health, Education and Welfare. Lee was told that The Comics Code wouldn't allow the story because it banned even the mere presence of narcotics. Lee gave the CCA the figurative finger, and Marvel published the comics dealing with the storyline without the Comics Code seal. After the story was given considerable praise from the general public, the CCA relented on changes to the Comics Code to allow for negative portrayals of drug abuse. However, the damage done to the Code by this incident was irreversible, and by the end of The Eighties, only Archie Comics and DC Comics (on a very limited basis) sought CCA approval for publishing.
How about the fact that he's responsible for the creation of some of the most popular Marvel superheroes ever made? Even if he made them with other people helping him, he still created them.
Crossing into Crowning Moment of Heartwarming, the fact that unlike many other comics writers of his era, he's lived long enough to see his characters' popularity expand outside the industry via several successful films.
Also a bit of a Tear Jerker since he sees the heroes he helped create decline slowly, with such comics as One More Day.