The first thing he printed was bibles....

Here's a little reminder. The Chinese have had movable type for a couple hundred to a thousand years by the time Gutenberg refined the technology into his printing press. Still, getting a reliable press like that into the common hands does a lot of things good.

Helped spread the Bible, and initially helped protestantism. But expanding literacy means expanding all forms of questioning, including religious questioning.

Prompted expanded literacy, which was virtually nonexistant in the hundreds of years prior, and increased knowledge. With this invention, eventually individuals were free to think for themselves.

Immensely important event. Arguably, the most important on the list. The event moves the written word into an accessible format, and opens the door that ultimately leads to large scale literacy, and after many varied permutations, what you are reading now.