What if certain bands/products/movies that had flopped in the past had been a success? Pick something an outline how different the world would be (even on a small scale). Think: New Coke, Waterworld, various games and their consoles.
Bonus points if there's a big change.
Final Fantasy: The Spirits Within
After the surprising success of 'The Spirits Within', Square Pictures began a long line of Final Fantasy films culminating with the announcement of a trilogy based on Final Fantasy VII. It seems after the strong negative reaction of XIII and XIV that movies rather than games may be the way forward for the series.