Here are some of the big innovations each company has done:

Nintendo:

-Really brought back gaming after the big crash with the NES

-First controller with d-pad, 4 face buttons and L and R buttons/triggers

-Put out the first game that let you save your progress

-Started the slim console trend

-First controller to bring an analog stick (N64)

-First controller with rumble attachment

-First wireless controller

-Revolutionalized motion controls

-Revolutionalized the handheld gaming market

-First controller with touch screen

Sony:

-First controller with dual analog sticks

-First controller with built in rumble features

-First console with a memory card

-Pushed the limits of disc storage to what we have today

-Introduced DVD and Blu Ray to home consoles.

Microsoft:

-First console with a build in harddrive

-Really pushed online gaming to what it is today

-First HD console

-First one to come out with Achievements/Trophies

(If there is anything big that I missed let me know and Ill add it)

this will be interesting

Edit - giving my 2 cents on the matter

i dont think anything can beat "saving the industry" so im going to say nintendo, also nintendo has been in the market for much longer than sony and ms so it has had more time to impact the industry more. however, i do think that since Sony entered the market, Sony has done more for the industry

All of them are good. Depends on each person

Nintendo. Nothing beats playing 1080p games in a Tablet.

Nintendo no contest.

All of those 3 have pushed gaming in every generation.

I think Nintendo did the heaviest lifting with saving gaming and creating Gaming God "Mario"
But Sony and Microsoft have andvanced gaming in the last 3 generations. I think those all where so fucking important for the industry and anybody who comes and tries do downplay the achievements of any of those companies should go and fuvk themeself

I won't quantify my opinion with a list, but in my view that honor goes to grand daddy Nintendo with the big bad wolf that is Sony coming in second. Microsoft should be commended as well. They did push the online gaming element to higher heights.

Nintendo

Nintendo. no contest

Thats kind of unfair Sony and Nintendo are doing it for a much longer time. I mean no doubt was Nintendo the most important gaming company. But Microsoft revolutionized online and this should not be downplayed.