Nintendo.
There can't be just one. From their revolutionary software, which gave gaming the huge boost it needed in the 1980s, to standardizing the Dpad. While Vectrex had analog in 1982, N64 popularized it. Nintendo has made countless innovations in both software and hardware. They standardized shoulder buttons—not the first, as XE 1AP Controller for SEGA Mega Drive was the first that I know of. Nintendo's handhelds redefined portable gaming. From ecominics. To the target audience. You think DS was the first to target casuals for Nintendo? A Game Boy came with Tetris for that reason, and commercials targeting businessmen in 1989.
Sony.
They took SEGA's playbook of targeting older gamers in marketing and elevated it to a further level. The dual analog, while not the first, as again that is the XE 1AP for SEGA Mega Drive. Helped standardize dual analog. The concept of a game console also being an all-in-one entertainment center goes back to the 90s. Pioneer Laseractive. 3D0. CDi and more. Sony finally brought it mainstream with PS2.
Xbox.
While SEGA pushed for online for years and DLC existed on consoles before even on N64 and Dreamcast. Downloadable games on DC. SEGANET while forward thinking. Xbox Live is one that really figured it out. SEGA intended to put a HDD in the Dreamcast along with a DVD drive, but was short on cash. So Xbox beat them to it. Xbox with 360 also helped kickstart the indie game revolution on 360.
Bite my shiny metal cockpit!
