10 Gadgets that Changed the World

"The wheel. The plow. The gun. The electric light. The radio. The chip. The untidy march of human ingenuity and innovation has led you here, to our list of the 10 most life-altering devices of the modern era."

http://blog.wired.com/wiredphotos6/2006/12/1_rca_model_630.html

Going through the list, the first one I was aware of as being something new that I didn't take for granted was the microwave oven. I don't recall them being widely used among people I knew until the early 80's, but maybe it was the late 70's.