Version Museum concentrates on the look of applications more than it does the story behind that redesign.
Version Museum showcases the visual history of popular websites, operating systems, applications, and games that have shaped our lives. Much like walking through a real-life museum, this site focuses on the design changes of historic versions of technology, rather than just the written history behind it.
It's a pity the selection of applications is so limited right now, but what is there is covered pretty well.
Looking at the Microsoft Excel entry mostly reinforced how much I loathe the Ribbon interface. I don't care how many studies Microsoft wave around proving that the average user prefers the way the Ribbon surfaces what Microsoft claim are the application's most-used features. Taking away the user's ability to add their most-used features to the Ribbon was (and remains to this day) a lousy idea.
[Via Daring Fireball]