1. Invented the feature length animated movie. A multi-billion dollar business that paved the way for Pixar, Aardman, and all the other great creators we admire in that industry.
2. Invented the modern theme park. The "Second Life" of 1955! This is another massive multi-billion dollar business. It is also impressive in its technical scope employing physicists, pyrotechnic folks, and a bunch of roboticists who work on the audio-animatronic robots.
3. The Disney "Imagineering" crew is probably one of the most interesting interdisciplinary groups around combining nearly every kind of engineer with every kind of artist to create amazing things on an ongoing basis.
4. Before he died he was applying his ideas on art and technology to urban planning. Not in the way you would expect (e.g. No mouse ears), but marrying ideas of "New Urbanism" with technological futurism to rethink how we live and work.
His story is also a classic one of entrepreneurial striving, failure, and an unwillingness to give up. Check out this book for more inspiration:
http://www.amazon.com/Walt-Disney-Triumph-American-Imaginati...
"Giant Steps: The Remarkable Story of the Goliath Expedition From Punta Arenas to Russia" by Karl Bushby
Unbelievable what it feels like to just take off...
http://www.amazon.com/dp/0751536954
"Walt Disney: The Triumph of the American Imagination"
The first third of the book is remarkable in that Walt Disney constantly struggles with failure.
http://www.amazon.com/dp/0679757473
"Swimming to Antarctica: Tales of a Long-Distance Swimmer" by Lynne Cox
Her story is all about single focus on doing what you want to do.
http://www.amazon.com/dp/B0013L8AQQ
"Born Standing Up: A Comic's Life" by Steve Martin
http://www.amazon.com/dp/1416553657