Well, they all have an equal impact on the industry, and Sony and Microsoft will have a large impact on the 3rd party with their big budget games. They would move to the PS2 for their more casual titles probably. Of course if one of the HD consoles left the party, then there would be less competition in that business, so we would see less agressive price cuts and Microsoft would not spend so much on getting all the games on their platform, because all the HD games would be going their way anyway, which would decrease how much they needed to do to keep their sales up, because the PS3 is their main competition at the moment. Sony would not do all this work on their online services. Basically, everything would be worse

It's funny that every single innovation you listed is only about making things "more" and "bigger", and not about making them "different". To wit:

online gaming - Expansion of offline multiplayer gaming.
optical storage media - Makes space for games bigger.
local hard disk media - Makes space for games bigger.
wireless controllers - Makes it possible to play anywhere, which is good; but Nintendo pioneered this too with the WaveBird.
motion controllers - Truly innovate, but again, Nintendo pioneered this.
usb interface - Expansion of interface options.
wireless communication - I assume you mean WiFi, which is again just an expansion of offline multiplayer gaming.
hi-def - Improves visual quality.

Let's look at the innovations by Nintendo which you didn't touch on, shall we?

d-pad - Makes it possible to play video games in a two-handed controller format comfortably, unlike joysticks, and expands gameplay options as a result.
analog - Allows for easier movement in 3-dimensional space, heightening the realm of control options significantly.
rumble - Adds vibration for additional gameplay immersion.
camera eye controller - Allows for pointer interface interaction, further expanding gameplay options.

Notice a trend here? All of Nintendo's innovation either adds new elements entirely to gameplay options or adds to the immersion factor.

Nintendo has done far more for video games than any other company.

I say Nintendo, because it has the Wii series for casuals, and they said if Nintendo goes down, then Mario/Zelda/Metroid/Star Fox/Animal Crossing go down with them, which had a bigger impact to the society.

you basically just dismissed my list for the sake of it, without proper reason.

optical media is now a standard in gaming, a standard that ninendo HAD to adopt if they were to compete.

the usb interface is now used as a standard in all gaming consoles, it's not a one generation thing, it has helped for a efficient method console expansion.

online gaming is NOT an expansion of offline mp, it's a new and INNOVATIVE method of mp. the same way an analog stick is a NEW and INNOVATIVE way of controlling a game.

Decline of HD consoles, the X360 can't compete with Nintendo alone. Also, with a dominating X360 M$ would make their console expesive (no HD/truly hardcore system as an alternative), games development on one, badly selling+costly system is not profitable, leading to the eventual decline of the box, helped by a cheap and great Wii system, which will look very good against a pricey X360. Wii remains the sole "competitor", games remain on near 6th generation technological capabilities, looking weak against the PC, leading to the consoles weakening (Wii will still hold its ground though, casual support+classic titles will keep it rather strong). Same scenario possible if M$ drops out, as Sony needs M$, and M$ needs Sony. What I've shown here is really the worst case scenario, it may over the top, but in the worst case, very possible. If you want, I'll tell you why I think Nintendo quitting is bad.

Cheers!

Eh, I don't think you're right about online gaming.  Multiplayer online is vastly different from offline - if you can make that argument, you can also probably say the analog is an improvement on the d-pad, and motion controls as well.  Also, to those who think it is, optical media is NOT something 100% necessary, I believe the DS has proven this.

Of course, the thing about online gaming (also hard disks, WiFi) is it was not born from consoles - it grew up on the PC.  It was inevitable consoles would eventually adopt this (the same can't be said about motion controls or rumble).  It looks to me like all Sony / Microsoft are good for is imitating either Nintendo, or computers - by simply following this plan, the industry would have shrunk, no doubt.  If there was no Nintendo to copy, what the heck would they do?  Of course, we'd never know for sure whose absence would hurt gaming the most, but because Nintendo has been driving virtually every innovation on consoles, they're the safest bet.

Remember, this question isn't "Which company would you miss the most?"  It's about which company is the most important to the industry, and so far i haven't seen a very convincing argument for Sony.  The most innovating thing they've done is give third parties more freedom, which is important no doubt, but I think Nintendo would have eventually figured out that had to be done (it isn't a very complicated solution).

Well, I wanted to just expand upon your points ...

Microsoft and Sony are both very good at evolutionary improvements, but these improvements tend to be very obvious because you're (essentially) taking technology that already exists and is being used for a similar purpose in another market and taking advantage of it. Optical media had been used for gaming purposes for years before companies like Sega or SNK decided to include it in add-ons for their gaming systems (see. Dragon's Lair), and online gaming had been toyed with on the NES and Sega Genesis with limited success and caught on in the PC market more than 5 years before Sega and Microsoft made it a core feature of their systems.

Nintendo is very good at revolutionary improvements, in particular to revolutionary improvements when it comes to user-interfaces. There is a reson for this that many people never seem to get ... Nintendo always has considered themself a software company and their hardware is designed to fit the needs of the software they're trying to build. If you get it in your mind that you want to build an amazingly simple user interface where a person can play a videogame using no more than 2 buttons you're probably going to seek out hardware to accomplish this task; when you find a direct pointing interface and motion controlls, and you see how these make gaming easier to approach and more intuitive you're going to base your controller on these technologies. You can imagine how someone created the "Vision" of Wii Fit and the balance board started to become an idea to fit the development needs ...

Sony is a hardware company, and they will always see a console in terms of the technologies "under the hood" and the user interface will only be a consideration for how to get people to use the "Real" system. Microsoft is a services company and they will always see the console in terms of the services it provides and the user-interface and console hardware is only a consideration for how to get people to use the "Real" system. Nintendo is a software company and the User Interface is the system.

Also, I had to add... I see people saying that without one of the HD competitors, the other would raise their prices and keep it expensive.  I just have to ask, why do you think they would do this?  Do you really think they would keep prices high when nobody is buying their product?

The only way I see prices staying high is when people are actually buying the thing.  What this means is, the gaming industry would NOT suffer - maybe you, the consumer does (having to pay a bit more to play what you want).  Of course, I'm not an expert on this stuff, so correct me if I'm wrong.

IMO, if the consumer suffers he will have less of a drive to keep up with HD gaming, and as a result HD gaming will weaken.