George H.W. Bush
A rare example of a living person with a retronym. Until his son, George W. Bush, also became President, George Bush rarely, if ever, used his middle initials.
Manual transmission (Also standard transmission)
Automotive transmissions were all manual, of course, before the invention of the automatic transmission.
Star Wars Episode IV: A New Hope
Originally released in 1977 under the title Star Wars. The new title was applied in a 1981 re-release after the decision to make additional films, allowing Star Wars to refer to the entire series.
World War I
Originally this was called "The Great War" and commonly believed to be "the war to end all wars". However, when a second war enveloped Europe, Asia, and much of the Pacific, it became necessary to distinguish them. Similarly, the 1991 war in the Persian Gulf, formerly called "Desert Storm" or just the "Gulf War", is now (since the 2003 invasion of Iraq) often referred to as "The First Gulf War".
Link (via Dark Roasted Blend)