For me personally it was my first home computer. Long before the Internet and inkjet printers, it was a Tandy 1000 and it changed my life in no small way.

Specifically I had written a small booklet of 24 pages. I typed it on an electric typewriter. It had words and simple illustrations that I drew and pasted on the page (no re-sizing). It sounds fairly simple. But getting the margins just right, allowing for the space around the pictures, I ended up typing the whole booklet all the way through 33 times! And I swore I would not write another thing without a word processor!

That computer had 128k hard drive and used the 5.25 floppy disks. But oh the joy of creating my own signs and posters! Printed them on colored paper because there was no such thing as colored ink. And of course more booklets.

My second choice would the portable phone. Not a cell phone, but a cordless home phone. I could walk anywhere in the house without tangling the cord or trying to stretch it just a little bit further to reach the sink. Sure, cell phones are pretty great, but I remember that first bit of freedom!