This is not even a contest. Nintendo is the answer. Not out of bias or preference but sheer contributions to the industry. I'll list several below that I don't think have yet been stated.
1. They introduced the 3rd party licensing model that still in use today. Without that, we'd have a dead 3rd party industry. Some irony in that, no?
2. They won several lawsuits to uphold IP laws, sales laws and more that would have basically killed the future of the industry had they lost.
3. They introduced Sony to the video game industry. Sony was selected by Nintendo to develop the audio DSP in the SNES and were later a partner in the ill fated SNES CD system. Prior to that, Sony had no interest in the video game industry. This means we'd not have an MS console either given they entered the market to counter Sony.
4. Nintendo introduced portable gaming as we know it today. While Milton Bradley's Microvision introduced removable cartridges (a dozen games that barely worked), it was Nintendo that really established their use. They also introduced things like headphone jacks, volume adjustments, multi-unit multiplayer, Even the first motion controlled games (Kirby Tilt N Tumble).
5. Game saves. The Legend of Zelda was the first title to include a battery in the cartridge which allowed gamers to save progress. Before that, you started over at the beginning for every game.
6. Online capability. The Famicom in Japan had an Internet modem add on that allowed for online banking, stock trading and and several online services. Though it couldn't do online gaming.
Combine these with the aspects listed many times already and it's quite clear that Nintendo has provided the greatest contributions to the industry by a wide margin.
The rEVOLution is not being televised
