This list also depends on how you look at it. I mean, We as a species are more than able to succeed and live without certain inventions. Without certain items, we as a species may no longer be around due to disease or what have you.

Some things are too specific. Like someone mentioned the Civ games, it all starts with simple concepts that humans have learned to advance. A printing press was a great idea, but without language and simple tools, it would never have been around.

Some may argue that nature showed us fire, and we imitated it, but will still learned the power and how to control it. Without such we would have been frozen in time. Simple tools like the lever, inclined plane, corkscrew, pulley, These and other primitive tools allowed us to advance engineering and the ability to create objects which later helped the spread of mankind. It depends on who ask what is truly important. Am I thankful for my PC and my internet, Yes! I wouldnt be here. I wouldnt have met my wife, but is it something that has allowed for the species to live longer and not die off. I dont think so. Mankind continued to thrive over the last few thousands of years despite computers. Our Printing press was a form of a primitive PC, which again, came about from language and simple tools. It all depends on how deep you look at it.

#1 Invention - Human Ingenuity. Finding those ways to make it no matter what problems have been put in front of you to face.